I did some research on this recently for use with my OEM step bumper. All the hitches I looked at were very similar, so I went by lowest cost. For me, that was by ordering one online from UHaul and picking it up at my local UHaul hitch center. It looks just like one of the others, can't remember which one.
None of the bolt-on hitches preserve ground clearance very well. That requires a custom hitch and possible modification of the van's frame, as well as the bumper.
Some have recommended using two receivers to support a motorcycle carrier.
Here's a reference to increasing ground clearance
Originally Posted by carringb
For ground clearance, you can mount the hitch to the upper flange on the frame. This will take some modification of the hitch and removal of the last crossmember (you don't really need it with a receiver in place). Then notch the bumper for the receiver. Or buy a bare receiver from Reese without end-plates and weld it directly to the frame. This method is probably easiest.