I took seats out of a 94' Explorer, and stuck them in a 84' std cab Ranger. I'm not completely positive about how I did it though (it was back in September and I don't have the truck anymore.
It didn't take too much work. Enough to make it worth it. I had to cut somethign unimportant off of teh seat rails, but I don't remember what it was, but it was just riveted on. The way I mounted them was kinda half-assed, but it was effective and works. I know I had to straighten the flange where the rails bolted to the floor on both seats, which all that took was a pair of vise grips. This was to adjust to the shape of the Ranger floor vs. the Explorer floor (The floor was flat in the Ranger, and on a hump in the Explorer.
Then I had to drill new holes for the rear seat mounts in the floor, and I think I also drilled new holes in the rear of the seat rail for the rear mounts as well.
After that I just bolted it right in.
If you have an ext cab Ranger, then it will probably be a slightly different install, whether it be simpler, or harder, I don't know
I hope that makes sense on how I did it. I'll try and remember to check this thread again if you have any questions.
Mjones's method of just switching the tracks sounds like it would probably be easier though!!