Having swapped 5 or so 4.0s and many other motors I'd say it's just about the easiest swap you're likely to get involved in. Here's my recommendations to make it quick and fire right up, 1st crank...
1) get masking tape, a ball point, a sharpie, a broadtip black marker, writing paper, plastic sandwich baggies and a digital camera.
2) Disregard the Manual when it says "disconnect xxx wire, then yy wire and also at this time the flux capitor wire..." etc. Find a method of labeling that makes sense to you, take a photo of a wire, pull it, photo again, and label it. Repeat until all the wires are pulled and labeled. I used to have a friend handy to hold up a card in the photo saying what I just removed, and write out the wiring/hose labels. Repeat with the hoses and linkages. Label them W1 or H1 for wires/hoses for example, continue with X2, X3 etc. til there's nothing left to label. Write your X1's and so ons with the sharpie and then write over it with the ball point, pressing hard so that if the marker rubs off or grease obscures the label you can still see the imprint left by the pen.
3) Maybe you remove the power steering pump bracket or the timing cover or water pump. Sometimes when you go to reinstall they don't make sense. Maybe some bolts are long, some are short and the rest are in the middle! DRAW A DIAGRAM, LABEL THE BOLTS AND BOLT HOLES. Put all bolts, nuts and misc. stuff in plastic baggies with a small piece of paper saying what it is.
I like to list the contents, EX: P/S pump BRKT bolts X 3...1 long, 2 short...
4) Remove the radiator, 1st thing. You will destroy it if you don't, believe me.
5) Have 2 or more friends to help you reinstall, especially with a manual trans. Trying to mate the engine and tranny will have you all screaming at each other, it's hilarious.
6) Replace clutch, hoses, belts and motor mounts. Everything is very easy to get to later if you need to, just plunk the thing in there and go.
Basically, you can't over-label or take too many photos. The 1st 4.0 swap I did was in the driveway in the middle of winter in Colorado. It was just about the worst experience of my life, or so it seemed at the time. I was so cold, I forgot everything when it came time to re-install. I threw alot of things around the driveway. Finally it ran, after about 90 things had to be re-done and re-done because I was lazy or impatient. Make sure your girlfriend/best friend knows that you will depend on them to drive you around at least a dozen times to the parts store/junkyard/party store. Tell them you appreciate it.