Nickerson State Park is along the CCRT, as well as having a number of paths within the park. It'd probably be pretty crowded during the summer, though (my only experience is in October) but so will anything on the Cape. There's a spur trail about 10 miles 'west' from Orleans (toward Dennis) that goes out to Chatham, but I've never been on that one. The CCRT is paved, well-marked, and there's plenty of opportunity to swing off to visit a beach, museum or historic site. (A side-trip to the National Seashore/Natural History Museum/Marconi Beach was recommended to my dad and me by an LBS in Orleans.)