I carry spare generator gas in a steel lined outside storage compartment in our Class C motorhome.
The compartment I use is not near the water heater compartment or the refrigerator compartment, so no open flame is near the conpartment with the gasoline container in it.
But here's the important part regardless of the type of RV - I use this type of fume-proof, spill-proof, puncture-roof, and rot-proof OSHA and NFPA Code 30 compliant UL/C-UL Listed and FM approved steel gas can:
http://www.uline.com/Product/Detail/H-1849/Safety-Storage/Type-II-Gas-Can-2-GallonExpensive ... but safety and reliability are priceless.
