Mira esto .. Creo que U son capaces de mostrar Google Map v2

Echa un vistazo a los métodos" decodePoly "y" drawPath " en AsyncTask

Imphasis principal en "drawPath" ..

PolylineOptions options = new PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
            for (int z = 0; z < list.size(); z++) {
                LatLng point = list.get(z);
                options.add(point);
            }
            line = myMap.addPolyline(options);

Complete la clase para su referencia ..

package com.example.androidhackergooglemap;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONObject;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.Polyline;
import com.google.android.gms.maps.model.PolylineOptions;

import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.location.Location;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.os.Bundle;
import android.provider.Settings;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Toast;

public class MainActivity extends FragmentActivity implements OnClickListener {

    private GoogleMap myMap;
    Polyline line;
    Context context;

    Location location;
    boolean check_provider_enabled = false;

    // Static LatLng
    LatLng startLatLng = new LatLng(30.707104, 76.690749);
    LatLng endLatLng = new LatLng(30.721419, 76.730017);

    public void onCreate(Bundle bd) {
        super.onCreate(bd);
        setContentView(R.layout.activity_main);
        context = MainActivity.this;

        // GoogleMap myMap
        myMap = ((SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map)).getMap();
        myMap.setMyLocationEnabled(true);
        myMap.moveCamera(CameraUpdateFactory.newLatLng(startLatLng));
        myMap.animateCamera(CameraUpdateFactory.zoomTo(12));

        LocationManager service = (LocationManager) getSystemService(LOCATION_SERVICE);
        boolean enabled = service.isProviderEnabled(LocationManager.GPS_PROVIDER);
        location = service.getLastKnownLocation(LocationManager.GPS_PROVIDER);

        // check if enabled and if not send user to the GSP settings
        // Better solution would be to display a dialog and suggesting to 
        // go to the settings
        if (!enabled) {
          /*Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
          startActivity(intent);*/
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
            startActivity(intent);
            Toast.makeText(getApplicationContext(), "Enable GPS servcies to use this app.", Toast.LENGTH_LONG).show();
        } else{


            try{

                String urlTopass = makeURL(startLatLng.latitude,
                        startLatLng.longitude, endLatLng.latitude,
                        endLatLng.longitude);
                new connectAsyncTask(urlTopass).execute();

            }catch(Exception e){
                e.printStackTrace();
            }

        }





        // Now auto clicking the button
       // btntemp.performClick();
    }


    private class connectAsyncTask extends AsyncTask<Void, Void, String> {
        private ProgressDialog progressDialog;
        String url;

        connectAsyncTask(String urlPass) {
            url = urlPass;
        }

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();
            progressDialog = new ProgressDialog(context);
            progressDialog.setMessage("Fetching route, Please wait...");
            progressDialog.setIndeterminate(true);
            progressDialog.show();
        }

        @Override
        protected String doInBackground(Void... params) {
            JSONParser jParser = new JSONParser();
            String json = jParser.getJSONFromUrl(url);
            return json;
        }

        @Override
        protected void onPostExecute(String result) {
            super.onPostExecute(result);
            progressDialog.hide();
            if (result != null) {
                drawPath(result);
            }
        }
    }

    public String makeURL(double sourcelat, double sourcelog, double destlat,
            double destlog) {
        StringBuilder urlString = new StringBuilder();
        urlString.append("http://maps.googleapis.com/maps/api/directions/json");
        urlString.append("?origin=");// from
        urlString.append(Double.toString(sourcelat));
        urlString.append(",");
        urlString.append(Double.toString(sourcelog));
        urlString.append("&destination=");// to
        urlString.append(Double.toString(destlat));
        urlString.append(",");
        urlString.append(Double.toString(destlog));
        urlString.append("&sensor=false&mode=driving&alternatives=true");
        return urlString.toString();
    }

    public class JSONParser {

        InputStream is = null;
        JSONObject jObj = null;
        String json = "";

        // constructor
        public JSONParser() {
        }

        public String getJSONFromUrl(String url) {

            // Making HTTP request
            try {
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            } catch (ClientProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                BufferedReader reader = new BufferedReader(
                        new InputStreamReader(is, "iso-8859-1"), 8);
                StringBuilder sb = new StringBuilder();
                String line = null;
                while ((line = reader.readLine()) != null) {
                    sb.append(line + "\n");
                }

                json = sb.toString();
                is.close();
            } catch (Exception e) {
                Log.e("Buffer Error", "Error converting result " + e.toString());
            }
            return json;

        }
    }

    public void drawPath(String result) {
        if (line != null) {
            myMap.clear();
        }
        myMap.addMarker(new MarkerOptions().position(endLatLng).icon(
                BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher)));
        myMap.addMarker(new MarkerOptions().position(startLatLng).icon(
                BitmapDescriptorFactory.fromResource(R.drawable.ic_launcher)));
        try {
            // Tranform the string into a json object
            final JSONObject json = new JSONObject(result);
            JSONArray routeArray = json.getJSONArray("routes");
            JSONObject routes = routeArray.getJSONObject(0);
            JSONObject overviewPolylines = routes
                    .getJSONObject("overview_polyline");
            String encodedString = overviewPolylines.getString("points");
            List<LatLng> list = decodePoly(encodedString);

            PolylineOptions options = new PolylineOptions().width(5).color(Color.BLUE).geodesic(true);
            for (int z = 0; z < list.size(); z++) {
                LatLng point = list.get(z);
                options.add(point);
            }
            line = myMap.addPolyline(options);

            /*for (int z = 0; z < list.size() - 1; z++) {
                LatLng src = list.get(z);
                LatLng dest = list.get(z + 1);
                line = myMap.addPolyline(new PolylineOptions()
                        .add(new LatLng(src.latitude, src.longitude),
                                new LatLng(dest.latitude, dest.longitude))
                        .width(5).color(Color.BLUE).geodesic(true));
            }*/

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private List<LatLng> decodePoly(String encoded) {

        List<LatLng> poly = new ArrayList<LatLng>();
        int index = 0, len = encoded.length();
        int lat = 0, lng = 0;

        while (index < len) {
            int b, shift = 0, result = 0;
            do {
                b = encoded.charAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
            lat += dlat;

            shift = 0;
            result = 0;
            do {
                b = encoded.charAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
            lng += dlng;

            LatLng p = new LatLng((((double) lat / 1E5)),
                    (((double) lng / 1E5)));
            poly.add(p);
        }

        return poly;
    }

    @Override
    public void onClick(View arg0) {
        // TODO Auto-generated method stub

    }
}

Espero que ayude. ¡Salud!

ACTUALIZACIÓN

Mira esto .. Creando OnDragListener para Google Map v2 Fragment

También marque esta.. Cómo dibujar una forma en el fragmento del mapa tocándolo usando google map V2

Alguna referencia más .. Cómo obtener coordenadas de pantalla de marcador en google maps v2 android

Así que tenemos alguna solución para dibujar a mano libre en el mapa v2. Implemente GoogleMap.OnMarkerDragListener en su actividad de mapa . Anulará la función onMarkerDrag.

@Override
public void onMarkerDrag(Marker marker) {

   //add the marker's latlng in a arraylist of LatLng and pass it to the loop
    for (int i = 0; i < arraylistoflatlng.size(); i++) {
         myMap.addPolyline(new PolylineOptions()
        .addAll(arraylistoflatlng)
        .width(5)
        .color(Color.RED));
    }
    }

Puedes pasar algún tipo de hackeo de mano libre como tan pronto como el usuario toque el mapa, tendrás que detectar esas coordenadas y pasarlas al onMarkerDrag . Como usted tendrá que utilizar la información de la zona para el proceso posterior. Para el evento táctil puede implementar GoogleMap.OnMapClickListener y obtener las coordenadas de su parámetro. Espero que esto ayuda :)

Este es el tutorial de Google maps API V2:

public class MapPane extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.map_activity);
        GoogleMap map = ((MapFragment) getFragmentManager()
                .findFragmentById(R.id.map)).getMap();

        map.moveCamera(CameraUpdateFactory.newLatLngZoom(
                new LatLng(-18.142, 178.431), 2));

        // Polylines are useful for marking paths and routes on the map.
        map.addPolyline(new PolylineOptions().geodesic(true)
                .add(new LatLng(-33.866, 151.195))  // Sydney
                .add(new LatLng(-18.142, 178.431))  // Fiji
                .add(new LatLng(21.291, -157.821))  // Hawaii
                .add(new LatLng(37.423, -122.091))  // Mountain View
        );
    }
}

Enlace : https://developers.google.com/maps/documentation/android/