When I do cruisers, I like to put them on their kickstand in the bed, straighten the handlebars so that the front wheel is scrubbing up against the bulkhead and will stay there, take the first ratchet strap and tighten it up so that it becomes taught just as it starts to apply pressure to the forks on the kickstand side of the bike. (I start ratcheting with slack, that way I know the fabric will grip before it gets taught). Then I go to the other side and tighten down the strap so that the forks are compressed. You have to get used to the travel of the forks and the lengths of the ratchet straps to get the right balance, but once you have it down you'll do it without thinking. It compresses the forks, pulls the bike upright a bit, and keeps the kickstand in contact with the truck. This gives me three points of contact (stand and the tires) plus the ratchet straps to the truck bed, and only a little pressure on the kickstand, so that it doesn't snap. I also always leave the bike in gear.
Dirtbikes and other upright types usually require a strap across the rear tire just to keep it from hopping, but I've never had a cruiser move, especially big one's like ours, with this method. My bike went 1500 miles fron CT to SWFL immediately after those pics were taken of it in my truck. It didn't move an inch.
The end of the VTX was the end of an era for Honda. They made AMAZING products in the early 00's. I bought mine used with 5k miles on it from a Honda tech who bought it new. Mines an 05 VTX1800 F3, so we have very similar taste! I will always have a HEALTHY respect for how quick this bike is, because it will break the rear loose by just cracking the throttle off idle while rolling. Love the way it handles, moves, and feels sturdy when you ride it. Short of a situation like yours where unfortunately you didn't have a say in it, I will never get rid of this bike.
Just noticed, and not meaning to derail any more, but, seeing how we're on the topic, what seat is that on your bike? One thing I do need to change is the F seat which pushes you forward right at the tailbone, and seeing how I'm tall and the bike is low, I don't need the extra push lol.