I recently purchased my 41'. I was just looking for a cool old truck and wanted to get something affordable. For me affordable was $1500 or less, a fixer upper. So when I was looking I took into account the condition of the truck and if it ran, or what I thought it would take to get it running. A running truck is way easier to stay motivated to keep working on. Then I made a list of things that I knew it needed and the what ifs'. I ran those numbers to see if I'd still consider it affordable then? I picked mine up for $2000, it had a great body for that price. I'm not a body man so that was worth the gamble for me on the motor. It took $300ish to get it running and driving, so the gamble payed off for me.
The year trucks your looking for go for about the same ammount in my neck of the woods given simular condition. I hope this helps if your looking for a project. A completely restored COE like mine went for $47,000 on BJ! That's a pretty big range to be looking in, just need to figure where you are comfortable in that range? I doubt mine will ever be that complete, but thats not what I was looking for.