I went for years with a diesel pickup and gas generator for my trailer. Never used wrong fuel in truck. Always carried a red gascan for the generator. Personally if I was in your shoes, I'd first look into some way of increasing the propane supply (preferably larger tank) and use the propane generator. One big advantage there is less exhaust odor..usually much less compared to gas or diesel. Possibly carrying extra propane would actually be less intrusive than carrying both another generator and gas to fuel it. The additional propane could also come in handy in cold weather.
