Is your tie point in the van on the floor? If so, I'm thinking you will be fine for a couple feet, but what happens when you get near the doorway, won't you be pulling it "down" [the cooker is still climbing the ramp, but the strap is pulling down to the tie point in the van]
If you have a tie point higher you could be fine, but I can't think of anything to tie to in my vans other than a seat anchor point.
Put the "old bat" on a camera.