So we went out yesterday and it was great. Since we waiting until the last minute (2 days before) to rent a boat the only thing that was available was a 25hp pontoon.
It was slow as hell but got us all around the lake which is what we wanted. We got to experience how large the lake is, how the islands look from the different sides, how scary the broads and witches are (they are not) and how to dock at the public docks.
Thanks everyone for the tips and suggestions, we were less nervous because of them! We're not planning our next trip with a faster boat. :-)
We really like bear and cow island but they're probably just a little too far for us drive then boat so we'll probably continue to look at sleeper and rattlesnake since it's an easy ride to west alton marina. We really liked the south west side of Rattlesnake, even when the other side was really choppy that side was nice and calm and easily swimmable. We were surprised at how steep the "backyards" were though, half the houses seem to be built right on the cliff edge.