Super nice gym and never too busy when I went.

Planet Fitness with showers (membership or get the free day pass online), also overnight parking in the lot.

Great gym, showers there we a ton of vans around 7pm, not 100% sure you could park here overnight but there are several options around Bend

Clean bathroom area with restrooms, showers, changing stalls, and lockers where you don’t need your own lock. Worth the membership price to shower here!