I chose 1" square tubing walls (16" centers) and roof (24" centers). Definitely upgrade or buy a trailer with Dexter axles, or Al-Ko. Mine have Al-Ko and they have been very good over 6 years of ownership. I picked standard leaf spring setup vs. 4" drop axles to gain ground clearance on mine. We also have twin bunks hung on vertical E-track mounted to the wall.
You can see roof studs here, (it does have 16" wall studs hidden from view in the pics), and you can see our simple bunks in the thread:
http://www.tnttt.com/viewtopic.php?f=42&t=48345outsidezion did some neat triple bunks:
http://www.tnttt.com/viewtopic.php?f=42&t=48345I second the recommendation of Homesteader if you don't mind a trip to Tennessee. I'd also buy another Cargo Craft if I were doing it again, but I'd want to open a dialogue with the factory to check off my custom options to ensure accuracy.
Welcome to the club!
Edit: reread your post, check out these two dealers, see what they can do on a Cargo Craft built in the Texas plant.
https://www.trophytrailerstx.com/https://www.randjtrailers.com/fwiw, the Texas Cargo Craft plant even builds these off-road themed trailers:
https://www.facebook.com/120847984634385/photos/pcb.1824495077602992/1824494720936361/?type=3&theaterDecide where you want your windows, (I copied gonefishin, two high up and opposite ends of trailer for great crossflow ventilation), add an RV door with screen, stab jacks at 4 corners, single step, 6" additional roof height, buy a trailer 2' longer than you think you need. It is not expensive to have the factory do these options, and I get to smile every time somebody wants me to demo the ventilation in the trailer.
Multiple edits, (need more coffee). I ordered a Cargo Craft Expedition model for the heavy duty options, but then used the axle/suspension from their Explorer model to get the ground clearance. Kinda threw them off a bit, but it worked out fine. They even allowed me to pick the exterior color (from their chart) to match my tow vehicle at no extra charge.
As far as brands go, I think Trailershowroom is an online broker/dealer for multiple brands, however several folks here have purchased through them with good results.