Man I can't say it enough times when it comes to Chrysler products. Transmission, transmission, transmission. Why can't Chrysler rub 2 cents together to build a REASONABLY reliable transmission in ANYTHING automatic? Beats the shit out of me! But all I know is that it is one of the FEW stereotypes of a product that I know to be ABSOLUTELY true. I'm not saying the truck is BAD, but I'm saying that I hope when you purchase it you are getting a good enough deal that you will be able to set aside enough for a transmission repair if/when it breaks if he hasn't had it overhauled/replaced already.
I really like the 2002 Dodge Ram V6 little work truck that I just bought. But it only has 75k miles, was well cared for, and already it does strange transmission things every so often (I live 2 blocks from work so it's still cold when I pull into my office parking lot, and it slams into R and D when I'm maneuvering around to park occasionally, sometimes the shifts on the road can be too firm as well). My Escalade with 13000 more miles has the strength and reliability you expect out of a GM trans. In any case, at the purchase price I got the Ram for I pretty much am accepting the fact that SOMEWHERE down the line I'm gonna need a trans-rebuild. I really do love the truck as basic as it is, but drivetrain-wise Chrysler products just lack. I REPEAT, I LIKE THE TRUCK.
My 1997 Grand Cherokee that the Dodge Ram replaced, had to be BOUGHT BACK by the selling Jeep dealer because the transmission was already toast when they sold it to me (again, perfectly cared for, 1 owner truck... the dealership didn't detect the problem because it only happened once the truck was good and warm from a half-hour of driving) at 113k miles (and don't even try to tell me 113k is the expected service life of a transmission you Mopar fanatics). I made 100.00 in my pocket on that deal since I had already cashed the check they originally sent me for the overage in taxes, but still, unacceptable.
That's a long-winded way of saying that the Dakota will be perfect for what you want it for, but you better be getting a HELLACIOUS deal on it.