Teddy,
I would have to agree with Capt. Ted, Shawme Crowell State Forest in Sandwich MA, just over the Sagamore Bridge on Rte. 6A is a great place to set up "base camp".
Last year, and for several of the previous years, it was $6/night and nice and quiet, even in the summer time. I usually make it over to SCSF 3 or 4 long weekends between May and August - my first this year will probably be over the Memorial Day weekend.
The Cape Cod Canal can be a great place to fish - if you have a bicycle all the better to reach some of the less accessible areas of the canal. I can remember many times when the stripers are feeding on the multitude of bait fish along the rocky shores o
f the canal (usually in the fall) and I mean along the shore. I've caught good size fish that I hooked withing 2 feet of the shore!
Good luck.
Craig........