Sounds like a perfect candidate for staying the course... Whatever you've done got you this far, no need to change it up.
As far as cooling goes, you don't describe when it runs hotter. Is it at idle? Running down the freeway? With the A/C on? Etc... If the radiator has never been changed, at this point it doesn't owe you anything, and they do lose some efficiency over the years due to deposits building up in them. Otherwise, fan clutch is another suspect, and same for the water pump if it has a ton of miles on it.
Nice rig. We enjoyed our 88 Cherokee for many years, till the lack of shoulder belts in the back seat meant it wouldn't work with booster seats for the kids...