When we run the generator, we can't use the outlet by the kitchen or the bathroom outlets. While in a campground and hooked up to their electric, we're fine. Are there fuses in the generator? We are in a 2012 Georgetown, if that makes a difference.
Do you have a 50 amp or 30 amp coach. If it is a 50 amp unit, there are two circuit breakers on the generator and perhaps one of them is flipped. That would power all of the loads on one side of a 50 amp panel.
This really has to be the problem if all works when connected to shore power. Check the generator breakers.