Some good ideas were mentioned already....... truck stops, campground
pay-per-shower, local gyms, schools, the solar shower, and i suppose if
you're really stuck you could prepare a hot bucket of water and do a
'sponge' bath.  Also if you're near rivers, lakes or the ocean then you can
always get some enviro-friendly soap and do a quick dip when nobody's
looking.

- Shawn.

> Are there unplumbed shower resources of which I am unaware?