I use a tow dolly to tow in vehicles for repairs, and I have towed both an Element and a Dodge van on it. No problem with either, have towed up to a full size Buick Park Avenue too. I just make sure that vehicle is centered on the dolly, and I make wide turns regardless of what I am towing.
The van may be too large for most, but that implies there are SOME dollies out there that will handle the van.
Simply buy one that is big enough for the van. Measure one vehicle and take the other with you when you go dolly shopping. I'd take the van, and measure the element.
Get the width between the front wheels, and the width to the outside of the front wheels.
2002 Chevy 3500 DRW 8.1L/Allison
2000 Palomino B1500
...and the reason why I need a DRW to haul a Palomino:
2004 United 7x14 tandem axle enclosed toy trailer
2011 PJ 8x20 7-ton deckover equipment trailer
Most of the dolly mfgrs will have a list of what vehicles they can tow...or at least, will have the measurements for the wheels, so you can measure the vehicles you have. I would think that most are pretty standard, so both vehicles should work on most dollies.
Often, the issue is the ramp angle, which may require that you get a few 2x6 planks, to run up onto first, so the bottom of the car doesn't scrape.
We are thinking the same way...as we would want to tow our Honda Odyssey, if we brought the whole family....but just the Honda Fit, if it's just DW and I.
Bill & Claudia / DD Jenn / DS Chris / GS MJ Dogs: Sophie, Abby, Brandy, Kahlie, Annie, Maggie, Tugger & Beau RIP: Cookie, Foxy & Gidget @ Rainbow Bridge.
2000 Winnebago "Minnie" 31C, Ford V-10
Purchased April 2008 FMCA# F407293 The Pets
The tire width on the vehicle you are going to carry is not where the trouble comes. The trouble comes when you turn the dolly fenders will no longer be aligned with the car wheels if the dolly has a center pivot wheel carrier. The dolly fender on one side will go forward and the other side will go back so they no longer align with the wheel openings. The dolly fender will put a dent in the car fender behing the wheel opening if they are not far enough apart. Been there-done that with a PT Cruiser. Sold the dolly-bought the Samurai and tow four down.