Cross the canal, get on Route 6 East
Take exit 9A or 9B whichever goes to Dennis
After about 1/2 mile on the left you'll see a big parking lot and a wooden and white sign for the Cap Cod Rail Trail
There is a bike shop right next to but after the parking lot.
Lots of gas stations and convenience stores nearby, even a Dunkins donuts with a bathroom.
It's a sweet 22 or 24 mile ride to Wellfleet. It takes me about 1 hr 25 min each way
GO GO GO
I don't have any links on this computer sorry