There are several boat landings on Squam. The one inbetween the lakes is the main one. Down by The covered bridge is another ($20) holds about 15 trailers, down the street half a mile from River's edge marina is a free one that will hold about 4-6 spots. Twenty years ago I used to launch at Sandwich beach it was free not sure the status on that landing.
Good luck Roland
I'm told (allmost positive) a town permit is required at Sandwich and they ticket cars without stickers. Some people say before Memorial Day they wont ticket you, but I wouldn't want to test them.
State ramp is realy super, but get there EARLY, shouldn't be a problem for most of you guys, we get up even before the Bass guys. Coming out might be busy however and Fish and Game and/or Marine Patrol will be sure to meet you at the ramp to check you out, be legal, especialy no live fish and legal lehgth.