For a nice 23 mile route, drive up Green Oaks (will turn into Dottie Lynn), like you are going to Eastchase and I-30. Once you pass over Pioneer (303, by Lake Arlington Golf Course), look for a park entrance to your right (it is small and is named Village Creek or something similar). The trailhead (concrete) is right there, and you can take this trail head all the way to River Legacy.
Here are full instructions:
1. Stay on the main trail, and after about a mile or two through the park and a neighborhood, it will put you onto Eastchase (still on the trail)...continue on riding past the Shell station on your left. After a few more miles (about 5), you will come to a massive park entrance. That is River Legacy.
2. Turn Left into the park, and continue on straight until you are in the very back parking lot (you will see a Port-O-John at the dead end)
3. Right in front of the port-o-john, hop on the trail, and immediately after the port-o-john, take a right and go over the little wooden bridge. Now you are on the main 7 mile park trail that will take you to the turnaround point.
4. You will see that the trail is newer about a mile in, and there is a fork in the trail. Stay to the left, and go over the big iron bridge.
5. Then you are home free to the mile 7 marker (Which for you is about mile 11.5). The trail dead ends here, and you can turn around and go back the way you came. Once you get back to the car, you will have completed about 23 or 24 miles. (I am not sure about the total because I ride from home to that park and it is about 30 miles in total for me).
Im gonna be out here tonight. Probably around 5. Not ridding to hard this week do to HH coming up.