The big inexpensive open frames are loud. Fine if you are out in the boonies by yourself but around others, they are annoying unless you are inside the rig with the AC and TV on. Think of someone sitting a big old noisy lawn mower right next to your site, firing it up and leaving it run at full speed for hours and you get the concept.
Now if you do boondock, the Champion 3500/4000 that can be had for $300. Around others I would get the quietest generator you can afford. For just charging purposes a Champion 2000 inverter is quiet and runs around $500. Two will run your air conditioner. The larger 3100i is a bit louder than it's Honda counterpart but half the price and will run the AC with easy.
We have a nice 3500/4000 with remote start for when we need it boondocking. we tend to leave it home in favor of letting the solar keep us charged up silently.