Congratulations on getting a boot patcher!
I don’t know if this will help Vridar, but I picked up and hauled one of my Singer 29K70 machines with a Ford F150 extended cab pickup truck. We put it in the cab. We put the entire machine, head attached to the treadle stand, in behind the passenger seat. We simply folded up the small back seat, folded forward the front seat, and tipped the unit in onto the floor with the handwheel end down, and slid it on in. It didn’t have the hand knob on the wheel, so that helped. I had enough head room for the stand to fit lengthwise up and down in the cab and get the door closed easily. Then I used blankets and the front passenger seat to trap it against the backseat to hold it. Worked just fine.
I just measured the length of my 29K70, and it’s overall length is about 29 inches. (Imagine a 29 being 29 inches long.) My machine is the short arm style, so it should compare about the same as the dash four. I don’t know if you’ll have that much head room in a minivan.
CD in Oklahoma