Thanks, Retraite.
So, it sounds like the hard start capacitor stores power and then uses it to start the a/c rather than overloading the genset. Forgive my lack of electrical expertise. I was thinking maybe the capacitor might somehow protect the a/c. The RoadTrek rep told me there is probably a hard start capacitor already in the new a/c, but he recommended either using the one in the Fedders, or buying another like it ($10 on ebay for an identical/same brand). From what you say, it sounds like I can't hurt either the a/c or the genset by doing the experiment you suggest.
Thanks!