Scotts advice x2. Plus--If you think something is wrong while driving: stop, figure it out, and fix it if you can. Most mechanical issues become bigger the longer you wait to address them.
You are going to get a lot of good advice from this crew. I picked up part of this list from another site a long time ago:
U joints (2)
Wheel bearings x4
Spare wheel nuts (2 or 3)
Length of electrical wire with some gator clips, and exhaust wire
Land Rover Workshop Book (you will pick up valuable insight from reading it, when it rains, the weather is bad, you are bored, etc...)
Besides spanners, sockets and T-45 torque hex
hub removal socket
Wheel Hub socket
Rubber mallet and small ball pean hammer
Oil filter removal tool
A good jack
2 axle stands
Hose Leak "Tape"
I am sure it will be a trip of a lifetime!