Don't use the type that makes a mist. It doesn't go deep enough through the camper. Instead, there is a type that gets hot and makes REAL smoke. It is activated with water. Open all the cabinets and close all the vents. Set off these smoke fumigators and they will penetrate.
I place each one on a ceramic plate just to be sure heat doesn't go through the bottom and make a mark where ever I sit it.
http://www.amazon.com/Raid-51528-Fumigator-Triple-3ct/dp/B002L35Z8Q/ref=sr_1_3?ie=UTF8&qid=1371001897&sr=8-3&keywords=fumigator+bomb