Changing a flat tire
How do you remove the under mount spare without having the risk of a crushed hand ... on a busy highway ... in the dark ...while it's raining? Wouldn't it be better to have it more accessible? I could get a receiver hitch spare tire mount but I already use the hitch for carrying bikes. My advice to XO is to do a spare tire winch like on a pickup.
Yes, quite the quandary, and most dangerous piece of the unit, not to mention if the shoulder doesn't exist or is uneven. I've opted for a spare hitch on the front to keep open the receiver hitch in back open. The back bumper won't support an attachment. It adds weight, but better than what you have described. I've also removed the spare and thrown it in the bed of my truck on long trips just to eliminate your scenario. It is a luxury since it is a truck.
Good Luck Thom. If you come up with another option, please post. Thank you.