Mowdoc-
Make darn sure your generator compartment has enough airflow that the door(s) don't warp or burn. Having had a place out on the island in Havasu for years I have seen that countless times as well-
121 degrees is no joke for those generators-
You will probably be fine but I wouldn't consider running my generator with the compartment doors closed if it is over 100 degrees. I think the doors warp and burn long before the generator will shut down. That said-
Running down the road you may get plenty of airflow but worth some thought...
Enjoy the show- No more holiday weekends at Havasu for us. Wife and I are too old and the kids are too young!
Safe travels good memories!