The last time I checked Sprinters and Ford Transit vans had a tow rating as high as 7500 in certain configurations. That is certainly more than enough for a smaller trailer but is right at the limit for our 28 foot trailer. The bigger issue is neither of those vans have a frame underneath them. Both manufacturers do not recommend using a weight distribution hitch (WDH) because of this. That severely limits what you can tow. I know there are people using a wdh with those vans, but when a manufacturer specifically recommends against that in the owner's manual you can count me out.

Good luck tomorrow checking out the class B van. That segment of the RV industry is hugely popular right now. It's an option that works well for many, and sounds like it might be the right choice for you.