Rust is really your biggest concern, and that applies to any 20 year old truck.
I daily drive a SOHC 4.0 1997 Explorer with 234,000 miles. It's 2WD, but has a torsion bar suspension like a 4WD or Edge trim level Ranger would. I've had plenty of things replaced on it (ball joints, fuel pump, water pump & thermostat housing, alternator), but everything has been available and the only way you would know it has 234k is by looking at the odometer. The prior owner had it for 20 years, so that probably has helped too. It doesn't get great fuel economy, but other than that 95-01 Explorers are great daily drivers. If it chews up its timing chains, I'm still probably getting another one or even fixing this one (not a single rip on the seats, crack on the dash, headliner bubble, nothing).
I also own a 3.0 Vulcan 2002 Ranger 2WD that I have had for 14 years. It has about 256k miles and has been a great truck over the years, but is getting tired. The engine acts up in colder temps until it warms up. I think it's camshaft wear. I put in a Motorcraft cam synchro back in December and that did not fix it, until it warmed up. Right now if I go and start it, give it a minute to warm up, and drive it, it would be fine. If it was 50*F outside though, it would definitely start bucking when I pull on to the main road and make a chirping noise at idle. The engine and transmission have never been out of this truck in its entire life, and the heads have never been removed, I know because my parents bought it new. It doesn't owe anyone anything at this point, and I'll keep it around as long as I can, but given the rough condition of the body probably won't rebuild/replace the engine. Never thought the 5R44E would go 256k miles, at least 10k of that towing trailers, and never have any problems.
Personally, I'd look for a government fleet 98-01 OHV 4.0 Explorer. As humble as they look, sometimes they checked every box like 4.10 gear ratio, limited slip rear end, tow package, etc. I'm talking about plain XLS with black bumpers and a tape player, government seal outline on the front doors, and 120k miles.
One more thing...while Explorer bodies are more prone to rust than the Ranger, the frames seem to hold up better. I had a 95 Explorer with no rocker panels, but the frame was fine.