Glad to hear you're sticking with it. The beauty of these (I've got two Range Rovers, from which the Disco was derived) is their simplicity and the ease of working on them. We've got quite a few cars in the household (14 at last count) and the Landies are by far the most spanner friendly.
I fully support your vision of puttingit pretty much back to factory with some gentle, camel trophy type, period offroad upgrades.
In terms of jobs to do while it's in it's current state:
- chassis protection should definitely be your priority, cavity wax would be a good way to prolong the period until you need to do it again, and a good fiber glass / rubberised paint as your topcoat.
- I'd have a good look at the prop shafts and UJs, make sure they're solid
- if it hasn't already got them as part if the snorkel setup, maybe lay the ground work for extended breathers from the diffs, fuel tank, gearbox, etc. That way if you ever end up axle deep in a muddy puddle again (I'd hope not...) you'll be in a better position as long as you keep moving!
- worth checking the handbrake over with the improved access if it's not had any work recently.
- depending when it was done last, you'd have decent access to do the timing belt. There's good videos of this on YouTube if needed.