The challenge with seat covers is that the seats are not Ford original equipment, not OEM. The seats are RV outfitter supplied seats that vary a lot by style and quality.
When an RV company, Winnebago as an example, buys a Ford E450 chassis for building a class C motorhome, it is a specific RV package that is illegal to drive on the streets. Here are some oddities that come to mind.
- no seats, only a disposable driver seat for "lot driving." It resembles a school cafeteria seat.
- no rear wall, just a stuck-on plastic barrier
- no carpet
- no headliner
- no outside mirrors
- two antennas, a standard one for B+ models, and a short one to clear the overhang of the class C bed above.
- interior ammenities like power windows & door locks, a/c, full instrumentation, etc.
- fancy chrome front grille work like an E150 passenger van has.
- a heavy duty alternator
- a radio is optional
and more.
So when it comes to seat covers, you really have two nice looking choices.
1) Buy new seats. Many people use this opportunity to upgrade their comfort.
2) Research who made the seats you have now, and buy from them, new seat skins.
From all I have seen, I would NEVER buy vinyl seats. Buy either 100% leather, or cloth. Since the great recession of 2008/2009, the vinyl fabric used to make seats has been imported from China. The material is inferior, lasting but 5 to 8 years before the vinyl surface starts to flake off the base material, and look like this.
Our rig was built in 2007, before the great recession. We have vinyl seating, but it continues to hold up beautifully.