If you are thinking about replacing the built in Onan generator, whether it be propane, gas or diesel with something quieter, I think you are out of luck. Onan has that market sewed up.
If you want a portable like the Hondas, you don't need 30A but you probably want more than the Honda EU 2200i or equivalent. That unit is probably maxed out running a single 15,000 A/C. A Honda EU 3000is or equivalent would probably work, but would not run two A/Cs at the same time. But with only 30A shorepower I doubt if your coach has two.
Note that it will take a significant gas supply if you are going to run 24/7. More than a single 5 gallon jug of gas each day.