According to the Indiana drivers manual, you can drive and tow anything if you are not commercial in any way. As noted, if you participate in sporting events were prizes are given, if you put a company logo on the vehicle, if you transport items for sale, if a business owns the truck or the trailer, and countless other things, you could be considered commercial. If you are commercial, you need a CDL over 16Klbs combined GVWR (not actual weight, GVWR as assigned by the manufacturer). You need the CDL for the type of vehicle you are driving (a fifth wheel is a combination vehicle) and you need an air brake condition (actually NOT a no airbrake restriction) if you have air brakes on anything. May I take this opportunity to say the Indiana DMV website sucks.
Brian