Good luck on your plans, Julia, sounds like a great adventure in the making!
I can answer one of your questions: the Brennan Recreation facility(public pool/skating rink) charges a buck for a shower(ok, the website actually says "$1.14"). It's adjacent to the campground, too, if I remember correctly.
link: recreation centre webpage
Have fun! Maybe see you there this summer...(on the rocks, not in the shower )
Sherri