OK, here goes:
1. I would say the the weakest part of the IFS setup is the idler arm. I have replaced many of them, they either get bent or the bushings in the pivot wear out. I don't think the CVs are as weak and flimsy as some people think, they get a bad rap. As long as you don't over flex them and run manual hubs so they're not spinning when in 2WD, they should last a long time. I have heard of some people busting the torsion bar socket on the upper A-arm, truck looses all suspension on that side when it happens. Never seen it myself, but some people carry a spare just in case. The front diff is only ~7.5" so a little weaker. Very few locker choices for this diff.
2. I think changing a CV is a lot more work, but you can prep your truck to make it a lot easier. If you remove the pressed-in studs from the diff flanges and go with regular bolts, this will really help.
3. Install grease zerks on your ball joints and keep them greased, same for the idler arm. Maybe get a beefier idler, there are several out there. Get rid of the stoopid drive plates on the front wheels, install manual AISIN hubs, disable the ADD system. Get some fresh grease in the spindle bushings, or upgrade them to needle bearings. Keep grease on the steering stops.
4. Wheel bearings are usually long life, as long as they stay adjusted and greased, seals are keeping water out. Spindle bushings do wear out eventually. Keep an eye on the ball joints.
5. Don't expect a lot of flex, unless you have made a total upgrade to longer arms, flexy CVs, etc. The usual "don't back up hard with the wheels cut hard either way", things go BOOM.
