I can offer some info regarding a 90-96 Dakota, I've had a few.

Up front, I'm not so sure there was much difference between the RH and the RE transmissions, as far as durability is concerned. It really comes down to how well earlier owners took care of the truck, or even more importantly, how badly they may have abused the truck. The answer is not a cover all deal at all (this model year truck is better then that model year is BS).

For what you are describing as the way your going to use your future truck, previous ownership is going to have much more effect on the transmission service life then weather the OD is hydraulic shifted or electronically shifted.

The next biggest deal concerning the transmission life, is if the antiflow back valve in the cooler line is, or has been cleaned or removed. That little ball moving back and forth in the line has a real problem moving if the fluid gets a bit dirty. When it no longer moves freely, it will kill a trans pretty quickly because it can shut off the fluid flow through the cooler. If the valve has been removed from the cooler line, then the fluid can drain back into the trans pan. If the last owner started the truck, put it in gear, and expected to move instantly, the fluid may not have refilled the empty lines and will starve the trans of fluid flow for a few seconds, causing premature wear. The Mopar auto trans does not pump fluid while in the park position (I believe the newer ones have solved that issue, but I don't remember when that started).

As a matter of practice, I always put my Mopar automatic transmissions in neutral for a count of 30 before I put in either drive or reverse, to give the trans time to fill up anything that might drained the fluid back into the pan. That sure has helped extend the transmission service life.

My 95 and my 96 Dakotas were both OBD2, but the 93 was OBD1, I'm not sure when the change over took place, but I believe the full size trucks were OBD 2 before the Dakotas were.

When you buy a used truck, buy the truck as an individual truck (this truck compared to that truck), not as a generic age group (there are good and bad in every age group).

Also, be sure you inspect the frame for rust! Take a hammer with you and smack the frame in any place that might look questionable. If it dents easily, or the hammer blows through, the frame needs to be patched. if it has holes that are not suppose to be there, they need to be patched. If it has any cracks, they need to be welded. Get a price on any frame repair before you buy the truck, some simply CAN NOT be repaired!

One more thing, very low mileage trucks mean they have spent a lot of time sitting (2,000 or 3,000 miles a year is a yellow flag). For a truck to sit for long periods of time is usually not good for them, if you start using them a lot, a lot of stuff might need to be repaired. Often low mileage trucks see a lot less maintenance because they don't see many miles very fast and most people base maintenance on mileage only.