I have a 2002 Durango that I bought in 2005. The only issues I've had (outside regular maintenance stuff) was the main computer motherboard went bad and I had to have it replaced at $600. The board that controls the remote fobs went bad - $600 to replace, so I use the key.
And about 5 years back, I had a weird issue where I would start up the car, drive it to the store, park and turn off the engine, go shopping, get back in the car and start it, and the gear lever wouldn't move out of park. After a 20 minute wait, it would move out of park and be fine. A few days later, the same thing would happen. Ended up, inside the steering column, the gear wire would somehow get caught up on the end of the gear lever. They moved it to a different position and I've had no problem since.
As for the engine, it's never given me a moment of trouble. And I towed a TT with it for 3 years - the TT was about the same weight as your buddy's.
Needless to say, I've been very happy with my Durango and plan on having it for another 10 years minimum.