That generation of Explorer can be real hit or miss. I've seen them running pretty good with 300K on them, and I've seen ones that needed a trans or timing chains (yes, plural) long before that point.
The trans is hard to service. No dipstick, you check fluid level and fill it from a special plug in the bottom of the pan...weird setup, and not DIY friendly. With maintenance, they are reliable. The problem is the vast majority will NEVER have the fluid changed.
As for the timing chains...the rattle may have been fixed by '05, but it could definitely affect an '02-'03...and basically you're just better off putting a new engine in if it happens because it's such a big job. You have a chain at the front and a chain at the back, so the engine must come out to service. Unless it has been perfectly maintained, a new engine is the best bet on these models.
Another issue is the thermostat housing. It's a big chunk of plastic with a radiator hose and a smaller hose that goes to the water pump, and some ports for sensors. They tend to leak after a while. You'll see telltale stains all over the housing and possibly coolant pooled up on the lower intake manifold. Not major, but it is aggravating. The little hose is a [censored] to get in place when doing the repair.
Other than that, these are mostly just affected by fit/finish issues. The body color plastic panel on the upper part of the tailgate is prone to cracking. I've seen a couple with poor gear selector adjustment, dead interior electronics, and other annoyance issues. They aren't really any better or worse than a Trailblazer or Durango from the same period.
Altimas from that time are actually pretty good. Once they fixed the pre-cat destruction problems, they got pretty reliable. For some reason they tend to wear out the serp belt quickly, and Nissan fit/finish in the mid 2000s was a little behind some other makes, but not horrible.
If I were in this situation, I'd go buy a '96-'01 Explorer 5.0 and call it a day. 5.0 with GT40 heads + solid 8.8 rear axle on leafs + Ranger frame = win. Who cares about miles/age? Plus, 14 years from now your daughter can be rocking a 302 Ford whether she wants to or not, rather than some boring car.
