If I'm camping in a dispersed area ie not campground, I'll run the generator as needed night or day. That doesn't mean I run it all the time, I don't like the sound either.
If it's very hot, that probably means overnight so I can run the air conditioning. If it's very cold, that probably means overnight so I can run supplemental heat.
The thing about noise in my opinion is it's relative ... A generator running next to a busy road or turbulent river or lake is going to sound very quiet. A generator running in the middle of the woods or desert on a calm day is going to sound crazy loud.
I don't believe in solar. The insolation is very low in my area and the weather not very cooperative. Gasoline works day or night, rain or shine.