Depending on your tow rig, available COVERED boat storage space, I recommend no less than an 18' boat. Wide beam is a plus. The lakes mentioned get rough at times. A wider, longer boat is a much more stable platform. Substantial horsepower is always a plus.
Buying a used boat is the way to go. Likely, a used boat will have electronics, trolling motor, canopy, SS prop(s) anchors, ropes, etc. Pricey items that are often included in a used boat sale. Be patient and you'll find a great boat in the used market. New boat pricing is great motivation to buy used.