Nice shakedown trip report. The rig looks great in the sunshine...
An option to get your ATV unloaded to run for parts would be to dolly off the trailer, cage your parking brakes, start up in gear declutched (manual trans benefit) and idle the truck ahead till you have room to offload, shut off in gear (manual trans benefit). Have your "swamper" walk beside and throw the chocks under the wheels where you shut down. Not recommended on 8% grades .
Spare filters, spare air governer, spare alternator, spare belt(s), kit of air fitting furls and o rings and stuff. If you have it along you never seem to need it...