I am in Virginia Beach. The Capital Trail is nice if you want to just ride, but not train. There are way to many walkers, hikers, and casual riders on the trail to get an adequate workout. I have a couple rides I do in Williamsburg that take you on parts of the trail, but we use them as warmup, cool down, or recovery from the actual ride.
I like to go to York River State Park and ride. My training partner and myself just did IM Chattanooga and used a course from the park to train for the hills. We could get 80 miles and close to 3k in climbing with very little traffic.