If you have a multimeter I would start checking to see if you have power at the incoming side of the transfer switch.
I pulled into a campground, plugged in and had no power. Tracked it back to the receptacle on side of camper. Pulled it off and found that it had been overheating and was heat cracked due to loose lugs on the wiring. It was still usable, so I tighten up lugs sealed it and replaced the receptacle when I got home. I have had so much trouble with loose or bad connections with this camper that I figure it must have been assembled on a Fri.