Mike you could use a 5 gallon, insulated, job site type drinking water jug, with hot water in it, and a bottle of dish soap, to wash your hands and wares with onsite. I use one for away cooks and I changed the push button valve to a small ball valve so it'll run/trickle non stop when I need it to.
Alternatively the handi wipes work well for hand cleaning and its always nice to have paper towels in the chuck box too.
I'll get my chuck box out and take pics later.