Really fun trails to go and ride for an hour or so. Not to large of climbs but it is still pretty hilly. There is one trail at the south end of monks park you need to look out for so you dont ride right into the water. Also, you dont want to find yourself on the trail next to the water at high tide, since it covers up at that time. There is also a really steep trail on the west side of monks park. There are no ramps, but there are maps and some benches thrown in random spots. Definitely tons of awesome scenery though. Great view of the water, and a good place if you want to kayak instead of ride for whatever strange reason.
From the Bourne Bridge, heading south, drive around the oh so wonderful rotary as many times as you would like, then take 28 south. Just past the little theme park called Adventure Isle, turn right onto Clay Pond Road. continue to the end and take a left onto Shore Road. Eventually you will go past a baseball field and the trail is just past that on the right. You can park at the little parking area on shore road, or continue on shore and take you next right onto valley bars and park there.
http://www.singletracks.com/item.php?c=1&i=2470