Fuel, repairs, tires, had to fix quite a few of ER's ******k ups, and being a west coast surfer guy, I had to pay for campgrounds every so often, as every dang pull off or beach from Vancouver, BC to San Diego says "no camping" and the police love to wake you up at 2:00am.. I got the thousand trails west coast and PNW pass ($1200) could hook up at any of the campgrounds for 30 days at a time. It came out to about $1,200 a month. and thats fuel, tires, repairs, campsites, discover and national park pass, food, etc.