The sound might be muffled but the next door campsite will notice if trying to sleep, so it would still be against most campground policies of quiet hours.
During the day running a generator is obnoxious for enjoying camping so should be only as necessary. Running appliances I don't consider necessary.
Solar wouldn't substitute for running a generator that I can see. Winter, evenings, and woods would negate that if you think possible. Battery power as in massive amp hours would suffice. I'm running my Keurig as I type this.
Though running a Class B engine is as obnoxious, It is more efficient with a second alternator to recharge batteries and in turn convert to 110 amp power and not cause storage problems.
However, I could store that boxed generator in my Class B short Sprinter if the box footprint is no bigger than 18" x 32" and no matter what the height. I wouldn't consider it for the above reasons and would think my inflatable kayaks, folding bicycles or cases of beer
would be more important.