GMT800 or Burban 2500 do I need/want awd?

What about the rear cargo opening on the burban? We have a 2010 Odyssey it would probably replace as the "big car" while we would keep my diesel sedan as our higher mpg car. We are able to use the Odyssey as a truck in most situation except for tall items that dont want to fit through the door.

Do you think I would be gaining or losing cargo space in that manner? Do the seats in the burban come out pretty easily?

The ideal sort of rig for me I think is something like the Jayco 272 https://www.jayco.com/products/toy-haulers/2017-octane-super-lite/272/

I don't have any toys but I like the combo of bunks+queen and the deployable queen over the garage area and the seating area also convertible.

Plus I am still thinking about karting in the future

Rear seat is a bench in the burb (GMT900, they are split), it folds or comes out completely. Not too difficult, just a big piece. The middle seats fold forward, and you have a completely flat floor. Plenty of room, can handle 4x8 sheet goods with the rear hatch (or barn doors) closed. The opening is probably a little shorter than the Odyssey.

Anything that doesn't fit in the Suburban can easily fit on a car trailer or small utility trailer. That is the trade-off you will have to deal with vs a truck.

That is true. But if I ended up with a toy hauler, you could put a ton in that just kind of a pain size wise. The small flatbed utility trailer is a good call

Or find a neighbor who has one you can borrow, thats what I do