I bought a 16 for $1,000 a couple years ago. I have no idea what year it is (around '80), but it had brand new sails and everything in good working order. So you should be able to find a good one for under $2,000.
My wife and I weigh in at about 350 pounds and we've found that you almost have to try to tip it over - although we are on a smaller lake. If you do tip, 400 lbs should easily right your boat.
Two years on this boat is about the extent of my sailing experience, so I can't compare it to other products. But it's been fun for us.
On Lake Ontartio you definately want to have some means to get your boat in if/when something breaks. The waterproof radio suggestion sounds good if you are not confident that another boat would see you.