Generator for Travel Trailer (not a tech question)

I'd run the cord. It's a lot easier to lift than a generator.
I once wired a friend's camper with an auto transfer switch. I installed a generator inlet and cord on the tongue and ran the wire for that back to the generator terminals on the ATS. This allowed him to just use a short cord from the trailer to the gen. in the truck bed. I think he left it hooked up all the time. Anytime they stopped and wanted power he just had to start it up.