install a rack and get a rack trunk
carry stuff to fix a flat: tube; patch kit; tire levers; pump
I change clothes at work. I have a shower now but didn't always.
you can stock pile food and clothes at work.
arrive before anyone else so you have some privacy
start small like by changing socks; underwear and under shirt.
then work your way up as it gets hotter to doing a simple sink type washcloth wipe down (bring a washcloth and hand towel)
for soap I like diluted neutrogena shampoo cuz it rinses well well used diluted and has virtually no fragrance.
with a cup you can do your hair head and face in the sick. the cup is for rinsing

party on Garth