It's one of the more simple swaps that are out there. Google it and you'll find plenty of info. Most if it is probably on TheRangerStation..
If I remember correctly, you'll need the 4.0OHV engine, possibly bell housing, engine wiring harness, and the PCM. Possibly the Y-pipe.. Yes, you could keep AC but it'd need recharged I think. Most of the rest is mostly plug and play. This is just off the top of my head though, so I could be wrong.