Oooooo! Maybe a Cache/FS - I vote FS - with snaps or clips to keep it anchored in the Truck(s)? Possibly oriented diagonally (side zip access) in the main compartment of the Pickup Truck, and parallel (top zip access) in the Monster Truck.
This is diagonal in the Pickup Truck:
The water bottle helps stabilize the laptop (2017 Macbook Air) but I wouldn't carry it like this - I'd put something in between to keep the bottle from clashing against the computer.
(I clipped a contrasting swivel carabiner to the handle as an anchor point for my key strap - so that I can see at a glance if I've thrown my keys in the Truck - otherwise they are swallowed up in the darkness!)
The laptop * can * stand on its own in the Pickup Truck, but very gingerly.
And here is the laptop inserted horizontally in the Original Truck - it would probably work better in the Monster Truck (don't have one of those yet):
Speaking of home gear, I would love a zip-away water bottle sleeve in the center compartment of the Trucks! (Similar to the one in the Luminary.)
And/or a way to stash a laptop in that central compartment - a Freudian Slip for the Monster Truck? Maybe one that opens either from the top or the side, so it can be used vertically/horizontally with either the Truck or Monster Truck. I'm always carrying things up and down stairs, and my water bottle/computer tend to be the h