I use Searchtempest.com to quickly scan all the Craigslist postings within a given radius of my house. I can specify a dollar range to avoid junk at the bottom end and I get back listings by area so you would see Truckee and then Reno and Sacramento and Yuba City and outward.
At this time there is a 1990 Ford F-350 diesel pickup with a 1991 cabover camper selling for $4900 in Corona, CA.
The more out in the boonies the seller is the lower the price as they have fewer possible buyers in their immediate area. The campers I saw for sale in the SF Bay area would go in days but those in remote areas like Bishop would sit for months.