Towing with a ford e series van

[TGK]

I'm interested in hearing from anyone who has experience towing with a Ford E250 or 350 series van, either cargo or passenger, regular or extended. I currently tow my '71 Safari with a '99 F250 SD SC LB 4x4 5.4L V8. I'm considering moving to a van for a variety of reasons. I'm particularly interested in input on these vans with the V10 engine regarding MPG and power compared to the V8. The V8 in my Super Duty does a good job of towing the Safari. The only place it feels like the truck is straining is when going over the steeper mountain passes in the NW. Otherwise, it's hard to tell the trailer is behind me. It looks like the dry weight of either van is less than my Super Duty, which is good. From what I could find online, it looks like the length of these vans would be 1 to 2 feet shorter than my Super Duty (20.5') depending on whether it was the regular or extended version.

Comparisons between driving the van versus a big pickup are welcome.

Thanks,

TGK