The rats that get into my chicken house simple ADORE the cedar chips we use on the floor. Cedar chips make a lovely soft carpet to walk on while they're headed for the chicken feeders! ;)
But for actual control in places like the house/RV:
My approach is to prevent entry as much as possible- stop up all holes, even those as small as a dime. But I never undersetimate rodents' cunning, so also set traps and check them regularly. I advise against the use of poison baits like D-con because the rats will often die in the walls and then one has another, MAJOR problem.