We have been to Lost Dutchman SP several times for multiple days and have never had a problem with rodents. Hope this helps.

I did not have any issues but everyone was leaving the hood of the car/motor home open.

Everywhere we camped in S Ariz last month people had lights under their rigs. We only have running board lights and left those on, took precautions about food etc and had no problems but we didn’t stay anywhere more than two nights. Long term, I’d check into lights. Blue seems to be a thing.

Pack rats. Yes. I was there for two weeks in early Dec 2020 and repeatedly found evidence under the hood of my truck they were present. Ate some of the insulation around the battery box and left deposits. Fortunately no damage to the wiring, but the Campground Host had problems the year before. Told me of a story he had about $700 in damage. That's why a number of people park with their hood up and/or put rope lights under their vehicles.

Not really. I have never seen any, but it is their natural habitat. In March rattlesnakes come out of hibernation and take care of any rodent issues, but presents a whole other awareness entirely.