There is a sound tent sold by supergen that brings the noise level of the 3500/4000 down to 65 db. That's the same as the Honda Handi or Champion 3100i off of Eco mode which they would be if you were running the air conditioner.
You mentioned solar earlier. We spent what we would have on a expensive inverter generator on our solar and batteries. It has made it so we haven't needed the generator in years. There are a number of people here with solar that can suggest places up there to get it for less than you may think.
We do have a 3500/4000 Champion that we should take but don't. Out in the boonies there is no one but us to hear it and it makes for a affordable, dependable generator that has the guts to start the roof air at altitude if we need it. That said I would never run it or any generator around others, if I could avoid it somehow. Pretty easy when you exclusively boondock. ;)