A pretty good friend of mine had one, mostly stock, an FJ40 actually. Tough little rig. Some things I remember are:
Everything was bolt on/bolt off. Doors, body stuff, etc. XJs are a lot like this too, but it was almost stupid easy to wrench on.
The motor, stock, apparently it like a verbatim copy of a Chevy straight 6, there are a few differences, so parts swapping isin't an option. Good luck finding parts. A lot of people throw v8s in them, I'd prefer a straight +6
3 6, I like the configuration (would a trailblazer one fit???). Also, its real low compression or something designed to run on third-world gasoline. Not speedy nor efficient.
Has a 4 on the floor tranny, low geared. Not really a good thing since the motor had LOW (think older diesels) redline. I read some article, apparently a 5 spd from some toyota sedan bolts on.
On the hand, its guaranteed to get a lot of WTF looks especially if most people on a trail are familiar only w/ jeeps or fullsize.