We pulled our 34 foot Limited with a 01 Ford E-350 for years. It made a nice tow vehicle. Ours had the trailer tow package with transmission cooler. The V-10 is smooth and powerful. Ours had a 4 speed automatic. The transmission would shift to 3 on "ordinary" hills and down to 2 on the steeper stuff. We towed at about 62 mph. I would recommend an aftermarket tachometer for it. You need it to judge engine braking speed going down hills. But I never added a tach to ours. Ours had E load range tires and I would highly recommend these truck tires, not a passenger tire.
The V-10 liked to fail ignition coils from time to time. I think we replaced 5 or 6 of them through the years. A rough idle and missing on wet mornings is a clue. Our van was a "one wheel drive" wonder, or rear drive with an open differential. This can give problems when pulling out on wet grass, up hills on gravel roads, and the like. There was one time on a steep hill where we had a red traffic light. When the light turned green, the van spun its rear tire. I couldn't get going. I had to drop the spring bars to add enough weight to pull up the hill. A bad experience. And I would get stuck with it every winter. I like 4WD a lot better. This is the main reason we traded for the F-350.
We averaged about 10 mpg towing, and about 14 in town.