When we were there in March, we used a generator occasionally during the day and heard some others running them as well.

Call Tusayan Ranger District 928-638-2443 to get answers.

I didn’t hear any but we were gone all day. Sites are far enough away from one another that it would probably be ok.

Yes you can. General rule is not before 6am or after 10 pm. Inverter genset is much quieter than a construction generator.