I am a long time Cummins fan and was fortunate to find a Blubird RE with 8.3 & MD3060. However, if I had not found this combo I would have been quite content with a DT466 & MD3060.
Don't discount the DT466. It is great motor. May not have quite the torque of the Cummins 8.3 but certainly up to the task.
I plan on hauling a fair size trailer behind mine and have looked over the frame configuration on my 2002 and don't see it being a problem. I cannot speak to other years but I know that the A3RE ran unchanged for several years.
Best of luck on your quest!!