Shower? I don't need no stinking shower!
But seriously, all you are doing when wallydocking, is having a place to sleep.
In the morning, wash your face at the sink, brush your teeth, and if need be, use a dry shampoo.
It's not a beauty contest, and after you live the rv lifestyle for a while, you will realize, nobody cares!
( woman speaking here )
Just an fyi, gentleman appreciate natural beauty.... It comes from within.
As far as coffee, use a stove top percolator.
Edit.... There are many better places to sleep overnight than Walmart or a truck stop.
Try Cabela's, casinos, Lowes, Menards, Home Depot, and Bass Pro Shops.
Freecampsites.net is a great website to find overnight places on your route.
If you don't have a battery bank, inverter, solar, or generator, sometimes it is better to just bite the bullett and pay for a campground. Passport America is cheap, I think around $25 to join, and has half price campgrounds across the Country.