Welcome to the forum.
25 years old vehicle will be past it's prime but still serviceable
Look at the gas, brake and clutch pedals for wear, that will tell you true mileage.
Test drive vehicle for at least 20min, that will give it enough time to warm up.
Beware of vehicles already warmed up when you get there, maybe nothing but could be a sign of a problem starting cold or cold running problem.
Pickup trucks often get rust in the rear leaf spring hangers and general rust in the rear.
2.9l was a very good engine , '86-'88 heads did have issue of cracking, '89 and up were better.
'86-'92 2.9l Ranger will use a Speed Density Computer for fuel injection and a TFI spark system with distributor.
These are OK but were older systems and did have issues as they got even older.
'90-'92 4.0l Ranger used MAF computer and no distributor, both better setups, and 4.0l had much better power.
Manual transmission is what you want on a 25 year old anything
Automatics will always need more service when they get that old.
Look for cut or spliced wiring, on older vehicles there were probably a few owners and they could have added 3rd party devices, and then removed them, leaving wires hanging.
While adding things is not bad you are relying on their wiring skills that it was done right.
Not all the years mentioned had CELs(check engine lights), but most did.
The CEL should come on when you turn on the key, thats the computer starting up and running a self check, then after starting engine it should go off.
No CEL could just mean a burnt out bulb...............but often means seller removed or blacked out bulb because of a system problem.
And when buying any used car/truck the BUYER sets the value, not the seller, seller sets Asking Price, buyer sets/determines actual value.
One good thing about buying a vehicle that's 25 years old...........all the Lemons are long gone, lol, only the good ones remain, but as much as I hate to say it even Rangers wear out