This seems like a really cool idea, I'm a big instant gradafication person, especially if you're going to be on the road for a while. The challange seems to me to be washing most of all, specifically water usage. How much of an issue that is varies with how much water you can carry, and how near you are to a water supply. Tempering water could be done with hot water from the stove, and an electric cooler plugged into a lighter socket, or a power inverter. Drying wouldn't seem like too big of an issue to me; I develop at home and dry my sheet film in a tupperware bin with lines strung inside it, and the top kept cracked to allow air flow, for sheet film you could hang inside a dry cleaning bag. Waste water could be kind of an issue if you're away from plumbing for a while, but your wash water should be able to be dumped anywhere (it'll only contain trace amounts of anything), fixer can be re-used quit a bit, probably a couple gallons of working solution would do you until you got home and could dispose of it, and is easy enough to carry. Used developer and stop bath could be carried until you're near a drain to dispose of it in, acctually stop bath can be re-used too. I'll be very interested in hearing your results and/or experiences of others who've done this, as the only things keeping me from doing a couple month long road trips are money and time.