The Pinehurst Branch area is a very pretty section of the park. You'll need a park map to find the connecting foot trails, but there's a nice wild walk here in the northern end that includes both the elevated Western Ridge Trail and the creekside Valley Trail. This 384-acre tract, previously called Dranesville District Park, has both wooded trails and more strenuous hiking paths along the Potomac River. Maps are posted throughout the park, which is unstaffed. Yes, if you don't act soon, you are going to miss your summer vacation entirely.
Space is limited.
Then again, so is time.