As others have said, RV generators are designed specifically for mounting permanently in or on a vehicle.
They have electric start, but no provision for a battery in the generator (as the RV has one) nor a built in battery charger (the RV's converter does that). Typically they also require 12V power to operate the control electronics and perhaps the excitation coils.
They have a fuel pump and no fuel tank, as they take fuel from the RV's tank.
They usually have a muffler and exhaust assembly that can extend out under the RV's skirting easily.
They have a provision for a remote control for starting and stopping.
They generally are 120V output only, not 120/240V output.
They're designed to run for long periods of time and have a long lifespan doing so, and be comparatively quiet doing so (at least when compared with open-frame contractor generators). Some portable generators are also designed for longevity, and some are not.
They're set up with the neutral and chassis ground bonded at the generator, while portables are not set up that way.
Having said all that, what you're envisioning sounds quite reasonable to me. Make sure you provide sufficient cooling ventilation, and of course leave a way to refill the gas tank when needed (and do other maintenance).
