05 Jeep 5.7 complete setup

I mentioned to a friend I work with I was almost 100% going to pick up a 74 duster, and had plans to eventually put in a new style HEMI. Long story short, he got a totaled Jeep Grand Cherokee 4x4 a few years back that only has 19k miles. He tossed up a price for the engine, transmission, complete wiring harness, $2500 but then came down to $1500. However, he did mention that the tail housing could be replaced to make it work in a 4x2 application. He knows this because he has the transfer case from his Rubicon bolted to the 55fre(?) {I don't know the transmission number off the top of my head}. The reason he quit working on his project of putting it into a CJ7 was the wring, he didn't want to spend $2500 on a wiring harness to make it work.

I have read a little bit about the different types of swaps that can be done to make it work, but the main question I have is what exactly would I need to make every thing work proper for my application? I don't want to go big cam or anything like that, just a fun little weekend beater with decent MPG.

I'm ready to start this project, but unsure of any obstetrical that will pop up.