I don't think there will be any "sliding out" after you remove the knuckle. If there was, you would have other issues.
If you've replaced a rear U-joint before, don't sweat it. This is pretty much the same thing once you get it out and on a workbench. The main difference from what I remember is that the width of the U-joints and/or shafts that the U joints go into is a little smaller so when pounding them out with a hammer (if you don't have a press) and putting them in, it's a little tougher because there isn't much room to get the one side out once you do get the other side out. It's sort of a tight squeeze and they're hard to get out sideways even.
One thing to watch for is the seal that usually sits on the outside knuckle. If it is still good and you want to reuse it, be careful not to ruin it while beating on the u joints if you're just simply using a hammer to pound them out. If you have a press, that's the way to go because it will be a lot easier and will likely prevent you from ruining the shaft/joint and other parts. But if all you have is a hammer and something round to beat with, you need to be careful.
As far as replacing other parts, ummm...check the parts in the outer hub assembly for the inner part of the 4-wheel drive hubs. I can't remember what they're called now but there are usually some plastic rings with springs around them that sometimes went kapput and needed replaced. I can't remember exactly which position these were in as you were taking the 4 wheel drive hubs apart but they are there. As far as a manual, you don't need that if you can take things apart and put them back together. As someone mentioned, you will need that 4 prong spindle nut tool though. They vary in size so you'll have to figure out which one you'll need.
Of course the obvious one would be to inspect your inner and outer wheel bearings and seals and plan on replacing if needed but at the very least, repack them with grease as needed.
--Ummm...am I missing anything else here folks?--
In some cases, I've had u joints stuck so well that as I was pounding with a hammer, I had to do so much pounding before they finally came out that it ended up bending one side of the shaft a little bit. In which case, once I finally got the new u joints in, I couldn't put the clips in because they were pressed out too far past the clip area. So, I had to do some pounding back into place. (not good on a shaft/knuckle).
One thing to do is give it a little heat if you want but then you'll likely ruin the rubber seal. Most people replace these anyway but if you're trying to get by cheap, you may not want to replace this seal. Is it something you "should" do? Sure. You bet. But is it "mandatory" and a sin if you don't? No. Although it is designed to protect the hubs from getting more dirt and debris in the bearings and so on, I don't know how many of them I've seen that were 50,000 miles past when they "should" have been changed and the bearings and other stuff they were "supposed" to be protecting were fine. Heck, a lot of times, there really isn't much left of the rubber and it's sometimes gone anyway. But, if you've got the extra $6-$12 per seal to spend, just do it and be done with it.
I'm sure others could weigh in with their tricks for putting U joints in or getting them out but once you get the old ones out, take a small screwdriver or pick and clean out the grooves on the knuckle end of the shaft where the clips go. Usually they get rusted up or get other gunk in them and you'll have a hard time getting the new ones back in.
If you can, put a little grease inside of the U joint knuckle area where each U joint with slide into as well as maybe a little bit around each U joint end. This "should" allow you to get each joint in a whole lot easier without doing too much "beating" on the shaft which could end up ruining a U joint or shaft. Also, put a little grease on the outer edges of the seals too to lube em' up.
Outside of that, once you get one side in place and put the first clip in, get the other side in place and squared up and put the last clip in. After that, I usually tap the ends of the joint areas on the knuckles at the head (the rounded end part) where the U joint goes into. I also tap the shaft area a little further down too. This way, it will usually free up the U joint a little bit and allow the U joint the move back and forth and up and down freely. If there is resistance in the U joint, that's not good and will just end up prematurely failing. So, make sure you get them in right and make sure they move well once you get it done BEFORE you put them back into the truck.
(Maybe you already knew all of this stuff I just mentioned but just in case you didn't or someone else was following along, I thought I would detail it out).
Other than that, other than inspecting the shafts for cracks and so on, there really isn't much else to go over that is different than another U joint replacement. It's just that the room to get the U joints out in the front shafts is "usually" a little less so it's sometimes a little trickier to get them out and in without ruining U joints and/or shafts. But if you've had experience and success with replacing rear joints, I wouldn't worry about it.
I never liked U joint replacements because about 20% of the time, they were a pain in the *** to either get out or in (or worse both). And....I would say I ended up needing to get another U joint about 1 out of every 25 or 30 times due to not having a press to get them in and out the right way or enough patience to deal with them. (probably more the last one). I'm usually pretty good on patience but U joints and me are not friends.