Even Doc (the Bear) has his limits - I guarantee he's using a hand truck for the harp seals, and a hydraulic table dolly to get it onto the prep table, then a chain hoist into the fryer.
You need to split the boxes into smaller chunks - if for nothing other than safety. A tall stack in a truck bed will be almost impossible to secure, and you don't want to go round a corner too fast and hear Fibber McGee's Closet crashing behind you...
The avalanche could take out two Beetles and a Smart Car, fatalities included.
I had a Basket Manlift fall over on a trailer once, and it wasn't fun. It was two blocks from the rental yard, and I had their Boss come look before we stood it back up. "Told you when I left that it needed more than the one ratchet strap, but noOOOoooo..." When your instincts tell you that, they're probably right. Listen.
You make the bottom box with big pneumatic casters and perhaps even a power drive system (Zero Turn Toolbox, 5HP Briggs and two Eaton 700 Hydrostatic Drives...) and that uses the ramps and winch. Then lift off the top box and mid box with a crane and stow them in the bed seperately.
Sounds like he needs two or even three of these rigs, because there will be a lot of overlap between "Big Lathe" and "Race Cars" toolsets. The common stuff goes in Mid Boxes and Top Boxes that can go either way, and you simply drop the "Lathe" bottom box for the "Race" one.
Best would be a second truck and a second set of hand tools just for the racing, and a really well secured garage for both so someone can't go "Shopping" overnight... - But that's blue sky dreaming.