Thinking of vans, here's the one I would order to tow your trailer:
2018 Transit-350 Cargo Van w/Medium Roof height
⦁ Regular wheelbase
⦁ 3.5L EcoBoost® V6 Engine
⦁ Gross Vehicle Weight Rating: 9500 GVWR
⦁ 3.73 Limited-slip Rear Axle
⦁ 6-Speed Automatic Overdrive with SelectShift®
Max. When Properly Equipped
Payload: 4,350 lbs
Towing: 6,900 lbs
The old Ford E-350 full-size vans have gone away, replaced by the more efficient Transit full-size van. They offer a diesel engine, but it's a weakling without enough power to tow much of a travel trailer. The 3.5L EcoBoost is a towing monster, so that's the engine you'd want.
The Transit passenger van does not have options for enough towing capacity, so you need to order a cargo van, then add a custom interior. Several van conversion companies will make the interior to your specs, or you can do what I did and DIY.
Years ago, I ordered the fanciest cargo van available, with finished interior walls and ceiling, but with a bare metal floor. Then I added plywood, 2" high-density foam, and premium Berber carpet over the floor. I found seats in a bone yard and added them. I installed a seperate sterio with headphones in the back, so the kids could blow out their brains with rock music while DW and I enjoyed our "elevator" music. My kids loved their roomy van for long trips.
Here's a comparable 2018 Ford full-size Transit cargo van I build&priced on Ford.com that would be a good starting place for building a custom trailer-towing van. You might have a hard time locating something like this on the used market.
⦁ $36,865 Base MSRP
⦁ $6,255 Total of Options
⦁ $1,395 Destination Charges
⦁ $44,515 Total MSRP
⦁ $36,865 2018 Transit Cargo Van XL 350, Medium Roof, 130” Wheelbase, 3.5L EcoBoost® V6 Engine, 6-Speed Automatic Overdrive with SelectShift® Transmission, 3.73 limited-slip Rear Axle
⦁ $150 White Gold. In the arid Southwest, you must have a light color paint, and this one is ideal without being a common boring white.
⦁ $485 Heavy-Duty Trailer Tow Package
⦁ $1,730 Cargo Van Premium Package
⦁ $450 Windows-All-Around, Fixed
⦁ $675 Privacy Glass
⦁ $655 Extended Length Running Boards
⦁ $95 Remote Keyless-Entry Keypad
⦁ $220 Long-Arm Power Heated Tow Mirrors with Turn Signals
⦁ $230 Trailer Brake Controller
⦁ $1,270 AM/FM Stereo with SYNC® 3 and Navigation
The above list does not any options that were included as part of another option, such as the cruise control that's part of the Cargo Van Premium Package.
Here's the link to get you started on build and pricing (MSRP) a 2018 Transit cargo van:
If you prefer GM, the 2017 Express passenger van with tiny diesel engine has these specs:
Trailering & Payload
GCWR (lbs.) 13000 lbs
Max Conventional Trailering (lbs.) 6500 lbs
The Chevy/GMC passenger vans will cost close to the same as the Ford Transit, but don't require a van conversion interior to get almost the same tow rating (6,500 for the GM diesel, 6,900 for the Transit 3.5L EcoBoost).
For the Dodge Boys, Ram also has a modern cargo van similar to the Ford Transit-350, but the max tow rating of the 2017 Ram 3500 window van is only 5,100 pounds, same as the Transit passenger van. Not enough to tow your trailer.