I agree, this is a very helpful list. I would add one item:
24 A Remove dolly wheel from tongue jack and stow it.
When I went to pick up my Caravel in a small town in Utah about 3 weeks ago, it was my very first day of towing a trailer of any kind. I was towing it from one end of town to the other, to get a feel for it, put air in the tires, check the brakes, etc. When I stopped at a gas station, some nice folks came up to my window and handed me my dolly wheel. I knew they were friendly, because they had such big smiles on their faces. :>) Good thing I didn't just hitch up and drive out of town.