I had trouble with pack rats a few years ago. They made nests in my class-B MH engine compartment and chewed wires etc. The neighbors have cats so I won't use rat poison (if a cat eats a rodent that ate the poison, goodbye cat).
I bought a mothball product that had a plastic hanger and hung them outside, one under the front, and one under the rear of the vehicle. I didn't have a rodent problem after that. There was minimal mothball smell inside the vehicle and that smell dissipated quickly when we opened the windows and went camping.
There's no proof that the mothball product worked. The rodents could have moved away or been killed by the neighbor's cats. On the other hand, maybe the mothballs were a reason for them to stay way.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.