The camper will not be slept in, it's just used for storage. The can is not something I'd carry with me all the time or even be full if I am carrying it, more like what Martin said...fill it at the jumping off point.
Fumes were my main concern, obviously the camper is not 100% air tight but it's not exactly open air either. The windows in the camper can be vented, but I'm not sure if it would be enough, though I do plan on using a high quality holder (specifically the one available from Adventure Trailer) and a high quality can (Scepter, etc.).