How many desktops can you fit in the bed of a pickup truck?

The van just stuff it till it won't hold any more Thinking I'd survey the load, move the stuff that best fills the van to the loading area(like larger things half height of van in first, then fill the gaps with smaller things, towers etc.) Be sure to pack behind the seats in a way it can't shift forward in a crunch, in a sudden stop things can quickly become projectiles. You'll need to load as much weight into the van as it will carry or at least close to that, for better traction on your drive wheels(be sure you check your tire pressures all around before leaving, as always check while tires are cold)
If there's a dock where you can pull alongside it lengthways, that might work to your advantage. Otherwise you might do best to drop the trailer and load the van first, then pick up the trailer and finish loading