The Cape is a wonderful place to go if you enjoy paved bike paths and beaches. From the short local paths (Shining Sea) to the long distance paths (Cape Cod rail Trail ~50 mi. round trip), there is something for everyone. What surprised us is there are a number of off road paths (see our Mountain Biking) section. There is also an active community of bikers in the area. The cape has to be one of the most outdoor active communities we have ever visited. Even the car dealer displays have kayaks and bike racks on the model cars in the showrooms.
Because the number of the bike paths on the Cape, we finally broke down the long one page version of Cape Cod Biking. For off road we have one page, and we divided paved paths into three pages; one page per region. The part that might be confusing is that the Upper Cape is the first part you get to after you cross the bridges from the mainland and the Lower Cape is the section with the curved tip that includes Provincetown. This will be clearly evident when you start taking roads marked East that clearly go west for which we personally have no comment on other than it is darned confusing. Perhaps people are more interested in beaching, biking and boating to worry about the road signs. That is our type of place!
The following map shows a few paths we mention on this site. I am sure it is not fully encompassing of all trails on the Cape. Just ones we have tried out.

http://www.capecodbikeguide.com/