I've fished the Accotink near Braddock road and around Wakefield Park. You can park next to the softball fields off Glen Park Road and walk the power lines before you cut into the trail. Or you can also just park at Wakefield and follow the bike trail.
It is hit or miss down there. I've caught a couple trout in the pools this spring, but recently no luck. I ran into a guy walking his dog and he claimed his son caught four about half a mile up the day before I was there.