Pilot - Flying J
These are great. They offer many amenities for the weary traveler. Many have dumpsites, and propane at reasonable pricing plus water, and secure boondocking. I have stayed at one for a couple of days. Don't know if that is acceptable but I wasn't bothered.
www.pilottravelcenters.com

Umatilla, Oregon
Date: 05/01/2014
Cost: $3.00
Location: Umatilla Marina and RV Park
Region: Northeast Oregon
www.umatillarvpark.com