I was going to do mineby sliding tge tcase and Trans back and decided not to.
Common knowledge is to pull the engine and Trans from the truck and do it on the crane or engine stand. Do you have either? Or drop the trans and tcase with a few Jacks.
Also there aren't cross seals, just a rear main and a block to housing seal. If you don't have a Welder buying a pre strengthend clutch fork would also be a good idea.
I'd also call around to machine and Napa shops to see who can machine or broach the flywheel flat while you wait. This will make it a one day job. You will need new locating pins for the flywheel as the old ones will be destroyed when removed... Grinding a flat surface on them and using a vise grip and slide hammer to remove. Thread on this topic:
Buy a lt77 input shaft seal just in case
Buy a plastic pivot and staple for the clutch fork as well.
Buy a HD clutch kit for a 110 or 130 (I used a Valeo in mine)
Buy a oem or genuine rear main
Have red scotch Brite pads on hand
Buy loctite bearing shaft mount or equivalent for the seal outer edge and moly engine assembly lube for the splines.
Buy black rtv or a tube of great stuff for the block gaskets.
You have the choice of either pulling the engine or dropping the trans and tcase. Trans and tcase are probably quicker to remove but harder to restab, you will also need a driveshaft tool (I've got one)
Think that's everything, and I wouldn't mind helping! Did e this job twice, once during a rebuild and once at 45k after a cheap seal died (lesson learned)