I have been on a learning experience with my 4Runner around general maintenance and knowing the components of my rig.
I figure it is out there in no man's land ( or with a group of folks) and the last thing I want is for something to fail that could have been prevented at home.
Considering it is a '98 a couple things I would advise is to go through is the running gear and really scrub it over ( ie check for leaks, dead seals, broken/damaged boots or rubber covers, check your bushings ( if you can ) and lubricate where needed ( ie drive shaft, any zerks really!).
Then do the check for cracks or weakened points (specifically around things like spindles or shafts).
If you can drain and replace the critical fluids, ( ie transfer and transmission ) then your off road confidence should be greatly improved!
Lastly, a scan-gauge is a nice addition if you do not have gauges for things like transmission temp.
Happy Trails!