Nothing sticks out in my mind as far as something to look out for. Check if the timing belt has been changed, along with other main. records and the normal stuff. My brother has a 98 and loves it.
The big differences between those two years are that in 01+ all models had traction/skid control and the 4wd system allows for 2wd and fulltime 4wd with a center locking diff. No rear locker option.
In 99/00 you could get the full time 2wd and fulltime 4wd with a center locking diff on the limiteds and a part time system on the SR5s. No traction control, but you could get the rear electric locker. Those are the biggest changes between the two, there may some things like different wheels or colors I don't know about.
2nd on the timing belt change, I think the recommended interval is about 90k. The water pump should be changed at the same time as they tend to leak at this age also. The water pump is to the right of the red circle on the lower right in the picture. Just follow the lower hose on the rad back to the engine. Is not easy to see from the top but if it's leaking you'll find coolant crusties.