If you're going to be towing anything (waterski, wakeboard, tube) then you need something with a water ski pylon or a full wake board tower. Also, an 85hp motor is probably going to be the bare minimum to get that done with 4 people on a boat. IMHO. Look for a boat that's already ready for the lake and they're trying to get rid of because they bought a new boat or something. Otherwise you'll end up getting someones project that they never finished...