I purchase boxes of moth balls (3 bags in a box) and throw a bag in each storage compartment as well as the battery bank and I place 2 bags in the engine area.
I have never had to use anything in the coach itself. This past year I failed to put any in the generator compartment and they packed the area with nesting debris...total cost to repair...$1,700.00.
Moth balls work!
https://www.walmart.com/ip/Enoz-Old-...3=2827&veh=sem