You would do better to find something that has less miles. Converting any truck to a trailer would mean extra weight to pull. If you want to make it into a puller that adds to your camping fun. If you have the time, the shop, and the money to convert it by all means give it a try.
I have seen a lot of these being towed in lately which means they are like old army units. high miles, they may put in a new engine before selling it, but there is a chance for many things to go wrong do to ware and tare.
if you are looking to convert something might look at these sites to see what others have done.
http://www.google.com/search?hl=en&q=co ... w&tbm=ischif you want a truck cheep old chevrolet SUBURBAN and old jeep cherokee's are going on sale very cheep. not the best of gas milage but lots of room to convert. And you can find parts anywhere.
I personally would be looking an old honda CRV it can get around 30 mpg.
your idea is fun, And I can see coming up with that idea too, but I see it impractical unless you have the bucks to make it work.
Thanks for bringing it up.