Wow, the Northern Tools hauler looks pretty good. I went a different route with some fabrication. I bought a used hitch mount dual motorcycle hauler that is capable of 600#. I cut and moved the brackets closer, shortened the tube, and elevated it up 4". The real beauty of this type mount is the ramp! makes loading much easier. No post to put up, just strap it like a dirt bike. They sell a cheaper version at Harbor Freight for single motorcycles that would work well.
FYI, Northern Tools gives a 10% military discount! Join their mailing list and get a coupon for discounts. My only concern on their mount is the weight limit they use. I had a Swagman for my regular bikes built identical. The weight limit was much less. Be careful if you want to use these on an RV. Their are a handful that are RV approved. The Hollywood mount is one of them I believe. Rad just got a shipment in.