Having grown up sailing Lasers, 505's, and J-24's out of Portsmouth, NH, I feel for you bro. The ocean water north of Cape Cod never gets above 60 degrees, get used to sailing in a wetsuit, even in July!

The other problem for beach cats in Maine is, there's no beach! Most of the coast is granite rocks, even the few 'sand' beaches you can find are not made of soft sand like in Florida (crushed seashells) but is made of crushed granite rock, so it is a much more coarse sand. Oh, and the tides are huge, not uncommon to see an 8' difference between high-low tide, so be careful where you leave your beach wheels if you go out at low tide!

There used to be a big Hobie regatta at Hampton Beach (NH) in the summer, not sure if that's still going on. Hampton has a very nice, long, sandy beach, but there's very limited access for a beach cat, not sure if they would even let you set up unless it was for that regatta.

If you want to race Lasers, there's a good group at the Kittery Point Yacht Club in the Portsmouth Harbor area;

https://sites.google.com/site/kitterypointyc/

Good luck, but the long winters up there are why I moved to Florida!