Jet ski's (2 stroke) I don't think are issue, you have to buy a permit to be on the water though. I have info if you need it. I brought my SEADOO 14.5' Jet boat last year (twin 85's 2 stroke). The lake is awesome, putting in in LG Township is exspensive though (again I have some info), If you drive around to the Vermont side or further up the lake there are public launches... The lake is 31 miles long, I ran the thing from tip to tip last year, incredible.
You wil see every type and kind of MC that exists, yes I'm serious. The town keeps a tight grip as stated by somebody farther up. They do not tolerate stunting, burnouts, excessive speeds(at least in town) and will bust you for pipes if your acting like an a$$. Follow the basic rules, behave and you can have an awesome time.
I meet an ever growing group of buddies up there every year and we have a blast...