I'll be interested in hearing someone respond to this thread, since I'm native of this area (but I've been transplanted to Florida), but I'm on the other side of the beltway in the Oxon Hill area. I can say there are plenty of hills in this part of Maryland and a lot of cycling trails/paths. Here's a link, but I hope someone who lives in this area responds soon. Silver Spring Bike Trails - Maps of Bike Routes in Silver Spring, MD