The only unlit pilot that would cause the propane smell would be the stove top - if you have the burners turned on. The water heater, fridge, heater, and oven should have a safety device that closes the propane if the pilot light is not lit (just like with a residential gas stove/heater). So again, if you're smelling propane, something IS leaking.
Newer class Cs tend to be bigger - I think average length is now about 27-32 ft. Older class Cs were often 20-24 ft.
A Class B is basically a van chassis & body with the interior customized for camping/living. A Class C is a van or truck chassis only with a "house" built onto the chassis. If you're exterior is not the actual van exterior, then you have a class C.
