Hi Rob327,
The generator prep includes an automatic transfer switch, wiring from the switch to the generator, wiring from the battery to the generator, and some modifications to the front compartment. You can purchase the switch from Amazon or other sources and can probably also get it from Heartland. The wire can be purchased locally. I'm afraid I don't know the details of what's done in the front compartment to prep for the genny.
The exhaust components have to be added as well, but I think they're part of the generator install, not the prep.