Hey I'm in Sandwich right now! I've been pretty over it for a long time but the bridge on 6a over scorton's creek was fun when I was younger and has people every day at high tide. It's pretty small (a bit bigger if you don't go at highest high tide but it still has to be somewhat high), but I've managed some dub corks and flips off it. Also in sandwich is the boardwalk, but its even smaller, easier to get out though.