Funny that crew cabs were "rare" in the past and now regular cabs are rare. With the chip shortage I doubt FCA is going to "finish" building your truck as higher profit higher trim levels vehicles come first because "money talks". Just saying.
Although the garage length is the main factor for a regular cab: don't forget a crew cab adds weight that subtracts from payload/camper ability. The transmission choice also affects weight as the Aisin is heavier. Just from weight alone one can consider a gasoline engine over the heavier diesel. Option packages also add weight.
I suggest a closer look at the Bighorn package. The manual 4x4 shifter is a Tradesman thing. It's hard to use that floor space unless you have 3 people in the cab. Heavy motors for a 4x4 shifter "What can possibly go wrong?"

Lack of use tends to FUBAR the GM 4X4 systems as the position contacts get dirty requiring several shifts to wipe them clean, maybe. The front diff is still electric. Even then shifting out of 4X4 with the manual shifter is a 3-Mile-Island problem: it's still locked up in 4X4, the damn light is off just like the reactor relief valve position indicator light indicating commanded not actual position, and the shifter is in the 2WD position. I never know before I turn if it's actually dropped out of 4X4 and going to turn or hop like a bunny.
I suggest power adjustable seats that have more range than the fixed standard seats. I miss the fog lights. A side light that goes on with the blinker would be useful although I am not sure if it's an option on these trim levels.
I would like a front parking camera. Without it I tend to back in and use the backup camera. My truck is long, the hood is tall esp. for short things that drop out of sight, and parking spaces are short before you plow into the pole or other krap stupid designers put or are required to put by ignorant local government in parking spots. There are other things in parking lots that cameras can help you aim for or avoid. It's an additional tool to use, but, you don't have to.
The 5th wheel tow prep is cheap from the factory vs. adding it later. It adds weight.
Are you going to wire AGM or other high charge rate house batteries into the truck from the camper with heavy gauge wire? Otherwise the 2nd alternator is dead weight. It's one more bearing to possibly lock up and strand you. It's not a automatic backup if the first alt fails without swapping some things around.
One last thing: make the dealer "EAT" the cheap low bidder TrashForce or other Firestone tires, all 5 (7 DRW Nexen) of them, and put some good rubber on the truck. Better life, no radial pull, better ride, maybe better traction.