I transport expedited freight usually 1-2 pallets weighing between 500-2250 lbs around the country in a 2018 Promaster 2500 with 245,670 miles of which 95% are highway miles, has the 6 speed automatic trans, and a 3.6L gas engine. Oils changed every 6000-7500 miles full synthetic. No major problems so far. Have replaced all coils when cylinder no. 2 was misfiring at 187,000 miles. Have had no other problems so far. I know that these vans can have electrical issues with alternator or wiring to headlights, transmission issues, and if idled excessively develop a tic. I will have the chance to buy this van at around 275,000 miles and see plenty of others getting 450-500,000 before rebuilding or replacing engine. Does it make sense to purchase this van with the high milage and not at a great discount or purchase one with 25,000-30,000 miles that has more city miles on it. I like the low milage part but it seems like such a crap shoot buying an unknown commodity compared to knowing exactly what I have and will need. I used to buy a car so I didn't have to walk now I have to buy them so I can feed my family and the wrong choice could be catastrophic for me. Love what you do for the people Scotty keep up the great work.
In your shoes, I would buy the lower mileage option.
You need something you KNOW is reliable. Highway miles are better than city, but a newer vehicle with lower mileage will usually have less problems. The engine may be fine, but that's a lot of miles on the suspension, brakes, bushings, etc. I couldn't chance it myself.