The Hampton Inn on Richmond hwy is located at the confluence of two major Interstate roads, the beltway and Route 1. It is isolated with no real easy route to walk anywhere. I DO NOT recommend a cab ride to DC, as it will cost you a small fortune to and from that location. I live closer by 2 miles and took a cab from my home to the Lincoln Memorial...cost $35.00 one way without tip.
You are, I will say, convenient to two different Metro stations within a mile or so. If you can't muster the shuttle to the Metro, then take a cab to the Metro station. Our trains are, frankly, the only way to get into and out of the city.
Hope this helps!