Front drive plates-I carry 2, but at least get 1
birfield
drive shafts
fusible links-3
EFI relay, fuel pump relay, any other relay that will stop the truck can't remember all off the top of my head
if you do not have a center diff lock switch get that and install it. This way you can drop the front driveshaft and continue if your not going to carry birfields, front diff, drive shaft etc
if you have a semi float rear, swap that to a full float, easy swap. full float spare shafts are smaller to carry than semi float and easier to replace in the field
change all belts & hoses before you leave and keep the ones you take off as spares
I do the same with plugs and wires, change and keep the old. It might run like ****, but it will get you home...
contacts/plunger etc to rebuild starter
I carry a couple of those big bolts that hold the lower control arms on, driveshaft bolts also
spare knuckle
coil and igniter
this is all on top of the basics that I assume you know, fuses, fluids, random nuts etc...
This is the short list. Most items I learned I needed after I needed them. I have been driving the 80 series hard since '95. It has only left me stranded twice, once a semi-float shaft broke and I had no spare, took us 8 hours to build a skid and drag it to a road, the other was a bad coil, luckily I had AAA and was near a road. I did have some weird electrical stuff happen after wheeling around Alaska on the Alaska Cruiser Trek a few years ago, but I'm gonna blame that on the numerous deep water crossings we did. What spares I carry also depends on who I am with. If I am by myself I take more stuff, sitting in Death Valley for 12 hours until somebody comes by can be a little nerve racking.
Good luck, and keep driving,
Nick