Thank you for your post.
Generator prep is a rather substantial option. This includes, special generator compartment box installed into compartment area, LP lines run from tanks, electrical junction box, plus run/stop switch with timer inside the coach.
The easiest way to have this option is to have the factory install when manufacturing. It is possible to install aftermarket, however this could become costly.
Check your coach to see if it is prepped, look for the switch and timer located near the slide room controls. If it is not there, it is not prepped from the factory.
I hope this helps.