We have a small plastic rectangular trash can from ikea 3 gallon FILUR -it snugs into the back of the driver's seat and pretty much stays in place...but yes we trip and kick it several times a day.
http://www.ikea.com/us/en/catalog/products/40188340/
we have never had more than 3 days trash and like other we try to minimize waste starting with our shopping.
Paper type stuff is tinder for the fire, some organics too like coffee grounds. Crush cans small. keep dry and clean and you can separate your common recyclables.
this is where once again I commend Oregon State Parks -which will allow anyone to dump tanks, recycles and trash at no charge- they will take a donation for the dump if you want.
Mike