I wondered what they were doing in that RV...

I was searching for some info about the grade % of the hill on Riverside going down to People's Park, and stumbled across something called the Naked Wiki. Apparently it's a heads-up about where you can go nude or find nude people.

People's Park

Sections of beach along Hangman's Creek, at it's convergence with the Spokane River, have a long history of clothing optional use. In recent years nude use has moved eastward, further up Hangman's Creek, where vegetation and shoreline provide greater privacy. Periodic checks by law enforcement, mostly to enforce county alcohol ordinances, are a possibility. People's Park is a county facility, with limited ammentities and no bathrooms. The park itself is fairly isolated for being so close to the downtown area; it is bordered on the south & west by Riverside Drive, on the east by the Spokane River and on the north by a bluff, atop which sits a cemetary. Usage on a typically warm summer weekend day would be 10-20 nude or partially nude users.