Originally Posted by Eurostar
(3) buy a shower head attachment for my 5 litre Ortlieb water sack, stand under it and shower with my clothes on. (how long will the 5 litres last? will it be enough to get the sweat out of the clothes?)
Discuss.
If you've got the water supply for it, I would use the Ortlieb sack and shower head to wash just the clothes, then take a shower yourself.
Note to Peterpan, there was a time when people bathed a lot less often than once a week. My father used to tell about a school classmate (Ohio, 1930s) who was sewn into his long underwear at the start of winter, and had the long underwear removed at the end of winter. In medieval times it was said that "a bath when you're born, and again when you're laid out, will see you through this world and into the next".
I agree with Rowan, merino wool in various weights is wonderful stuff for socks and upper body garments. Synthetic cycling shorts are still nice, though, you can rinse them out quickly in a sink and they dry quickly.