If you are doing this for your own or friends consumption (like the camping trip above), You can surely bottle in plastic bottles as long as the bottle can handle carbonation (i.e. was for coke, pepsi, root beer, etc. and not juice), the lids have good threads and a rubber/plastic 'gasket' (for lack of being able to find a better word) in the cap, and you store any non-brown bottles out of the sun-light. As mention above you won't be entering these in "shows" (most homebrewers don't enter shows anyway), but this doesn't mean you don't "make the best possible beer" as stated above (glass IS probably better for it, but there should be no discernible difference if drank within 1-3 months and stored out of sunlight).
If you try to keep these for 6+ months and/or store them in a lit room, then you will probably run into a problem with ruining your beer.