I had a packrat building a nest under my E-150 battery box. Was parked on a gravel pad next to my mom's house in the country, bushes and trees very close on two sides, house wall on the other. Early one morning I heard strange noises and thought a squirrel was on the roof but the sound seemed "under" not "over". Remembered reading about packrats and thought, Oh Please! Not that! Sure enough, raised the hood and there was its tail sticking out from under the battery box, could just see leaves and twigs. War was declared!
I cleared out the nest as best I could. First thing, I got in and blasted the horn. Nope, he kept snoozing away. Bought some granular repellant stuff and spread it around the van and under the hood (pee yoo! Stinky!). Set big traps underneath and at the wheels. Left the hood up at night with clamp on work lights. One evening, when I raised the hood to set up the lights, there it was sitting on top of the radiator, a foot away. Startled me so badly I stepped back and the hood slammed down hard. Bang! Who was more scared? Took the van to a car wash and thoroughly cleaned the engine compartment with the high pressure sprayer. This went on for a week! What worked? None of the above. I left. Packrat 1, me 0.
Also had mice in my fifth wheel underbelly storage compartment, parked in an RV park. Always in the fall. Removed everything, cleaned with bleach water, set traps and poison. (At this point, my "never use poison" attitude went down.) Stuffed steel wool in every possible entry point that I could find. Not easy around the slide out. Set up rope lights all around outside. The second year, they were back. Chewed the wire to the outdoor patio lights! Cost $150 to fix. I hate them!
I am an immaculate housekeeper. All food is in hard containers or the fridge. Never had any in the living spaces. I became crazy about cleaning.
I bought a BB gun and would sit outside and shoot at squirrels. Luckily, my RV was located away from others. Neighbors laughed. Hell, even the squirrels laughed as they ran around on the roof. I cut back the tree branches, they just jumped across. I had my Class B parked in the middle of the driveway. One squirrel ran underneath it once and I went ballistic! I ran after it, cursing and screaming, throwing rocks, it was WAR!! My friend and neighbor was over and she just howled. She said she didn't think I knew those words. I turned into a raving maniac. Mess with me, okay. But you better step away from my Van!!
That was over a year ago. I can sorta laugh now (back in S&B), sorta.