There is some amazing work here, and I love how much attention to historical detail people are using here. Frankly, I got sick and tired of all the people modelling vehicles on flat cars with tops on Jeeps and crew-served weapons still mounted in place. Neither happened in real life as the tops would be frayed and the machine guns would have 'walked off,' (imagine having to explain that to your CO when your vehicles got to where they were going).
FYI, the canvas on military vehicles in WW2 was OD green, not a tan shade. Nor were the seat covers tan. It was all OD green (called OD #7, the same type of shade the vehicles were painted with) and the vehicles were actually painted in a semi-gloss that sadly nobody is able to reproduce today for restored vehicles.
The only WW2 soft-skinned vehicle that didn't have OD green canvas seat covers was the WD-series 3/4 ton Command Car. Those had leather seat covers.
You can see what it's supposed to look like in this shot of my living history group's vehicles at an airshow display a while back (my own 1944 Willys Jeep is the second from the camera):
I used to be a US Army officer, mostly in heavy mechanized units. I couldn't count the number of vehicles I saw loaded and off-loaded at railheads...
Sadly, as I model narrow gauge, I can't have anything bigger than a Jeep on a flat car. I matched the canvas windshield cover to the one on my own Jeep...
Lots more where that came from elsewhere on the layout. I have a few Jeeps (one with a .30 caliber machine gun mounted on a pedestal, with the ammo can removed as was common in stateside training), 3/4 ton Weapons Carriers, a Studebaker 2.5 ton US6, a GMC 2.5 ton and a Chevy 1.5 ton. All the large trucks are very difficult to find (and expensive) models sold only in Europe:
I also have a pre-war Ford, but I removed the unit markings from the door as a few of these were still in use by the end of the war stateside:
They're all 1/43 scale. I also have a small group of 1/48 and 1/50 military vehicles, which are in a tree line at the back of the layout (for a small bit of forced perspective). Only one visitor has every noticed them way back there.
Noticed none have the 'surround' US star, as that was a European theater thing. Stateside vehicles had the simple white star (or in some cases, support command insignia in place of that star).