Difference in a 30 amp rig and 50 amp rig is a 50 amp rig has 2 or more AC units. You still will be plugging your shorepower cord and whatever appropriate adapter no matter the size of genny you get. If you need to run 2 AC units you are looking into a 5K watt or larger genny, one AC unit will require at least 3K watts for reliable service at varying elevations.
If you don't plan on running any AC units a 2K watt genny will run most everything in your RV including most microwave ovens. We prefer camping off the power grid and would never leave home without a generator. We didn't buy a camper to have all the amenities of home just to scrimp on our DC usage, we want to be able to use our rig and all it's amenities.
We use an inverter and a battery bank to power our HD tv and HD satellite, dvd player, Bose sound system, laptop pc, and for charging our portable electronics. We have solar as well and it is effective for charging our battery bank, but in many cases weather or trees cause less than stellar charging performance. In those cases running the genny every other day for an hour or two allows our Iota IQ4 converter to quickly restore consumed amphours.
All generators make noise. Inverter generators produce less noise, but can be pretty loud when providing power under heavy demand. You can pair a couple of units to gain enough wattage to run a 15K AC unit and you could leave one home if AC usage will not be required for the trip at hand. Honda and Yamaha build high quality units and they are available in a variety of sizes.
A popular choice for those that don't want to over spend on an item that in most cases will get little use are Champion generators, and they come in both inverter and open style models. Most report dependable operation and good customer service when the need arises, these units can be had for a fraction of what the red and blue units are currently selling for.
Figure out the max watts you will need at any given time and go a bit bigger as elevation can reduce total wattage capabilities. Determine your budget and use the internet to view the many options available. Generators can be a useful item to have when RVing but they must be used within whatever rules are in force at the campground should they have them. They do require a bit of maintenance and should be exercised occasionally if not being used often. Enjoy your new generator, it has saved the day on many an occasion for us.