Hey, welcome to the scrum!
Sounds like you are going about it all in the right way, although, I, too, would take a short shakedown trip close to home for a first test of the new rig, just to make sure everything is functioning as it should, but also to help you find those small purchases you won't have thought of before hitting the road.
The trip to Denver and points west sounds like fun. But do be aware that September starts the early snow season in the Rockies. Last time I passed through Colorado, I recall seeing notices along the interstates that truckers are required to carry chains beginning Sept first. So you are no doubt going to want to head south fairly soon.