I'm going with 147,000 miles. It's a guess, but check out the brake pedal. It looks like the rubber is worn through. I have a 1997 Chevy diesel crew cab that has 83,000 miles, and the pedal doesn't look anywhere near as worn as the one in the picture. The rust, in and of itself, does not say anything to me though, as far as mileage is concerned. The brake pedal is a dead giveaway...but more importantly, I'd judge it on how tight the steering feels and other indicators (e.g., any blow by, etc.). Regardless of whether it is 147K miles or 47K...if it runs well, shifts well, and stops, you have yourself a good truck. Some on here have commented (recent posts on an old thread on towing with a CUCV) that these trucks rarely see 200K or higher miles. I have heard of guys getting 300K+ out of their trucks. A guy I used to know (named Ernie from the South Jersey MVPA...not the older guy, but his grandson) had something like that on an M1009. Good luck with the truck!