First of all, I am new to this forum and new to Ford light trucks. I have owned F150's but never ventured into the smaller trucks. So any insight into my questions would be greatly appreciated, and respected. Thanks in advance for any responses.

I am looking at buying a small truck, and have had Nissan Frontiers in the past. I have found a 2002, Ford Ranger, 4x4, Edge series. This truck has 89k miles, is auto, and so far I have gotten the guy to commit to $6200, but if I decide to sell it in the spring, I think I need to be around $5000-$5500 to make anything on it after I detail it out, add a receiver hitch with plugs, and possibly some nurf step rails. I may end up keeping it, but not sure at this point.
Before I get it, I want to make sure it will perform at least as good as the Nissan. I live in the mountains of Colorado, and need to be able to handle the passes, as well as tow the same as the Nissan.
How durable has this year and series been, and what were inherent issues if any? What should I look for before pulling the trigger?

 

Overall, trucks like this can be very strong and ling-lasting. Don't exceed payload and towing specifications.
$6200 isn't bad for 89k miles, if it's well maintained. I think bargaining down toward $5k is warranted and a good idea.
My opinion is that the automatic transmissions are probably the weakest part of most trucks as they age. The Rangers aren't the worst, however. If the fluid & filter was changed at proper intervals, it could be good for a long time to come.
What engine does it have? I assume 3.0 V6 or 4.0 SOHC V6. Both can be very long-lasting, but the 4.0 is much more satisfying to drive, and it doesn't use much more fuel than the 3.0. You would hate towing in the mountains with a 3.0 Automatic!
Also, REALLY check the truck for rust. Make sure the A/C works well. Make sure the 4x4 engages and drives properly. Auto locking hubs are not preferred by most who do work with our trucks.
I generally feel that the Ranger is 2nd in quality to the Toyota Tacoma, when similarly equipped, not factoring the frame rust issues Tacomas have had in the past. Rangers are usually a lot cheaper, too.
Good luck, post back with the truck you buy, even if it's not a Ford.

 

I have an '04 Edge SCab Stepside as a DD. Bought new, and always maintained. 3.0, 5 spdman. One problem area the Rangers have/had, are the rear shackles and shackle hangers. They're known to rot out from crap sitting on top of them. Another area for rot, is the bed floor towards the front, and the bottom of the right door.
Longevity as far as the 3.0, the engine has had no problems in 170K miles, I'm even on the original clutch.
The 4.0 would likely be better for power where you are, but you still won't win any races.
Having never ever bought asian vehicles, well, there was one POS, and I've never considered one favorable, so my comparison would be quite biased.
I wouldn't mind finding a Ranger like you're talking, they're great little trucks. I hope the new ones turn out as good.