Trip to Sportsmobile Austin

I am back in Texas tomorrow and moving into an apartment for a few months.
I am just down the road from Sportsmobile. I want to stop in and talk to them about building a class B sprinter style van.

I don't think I will have them do it because the waiting list is about a year long.
BUT.... I want to ask some questions so I have some ideas when I go talk to the company that I am going to have do it.

I have alot of research to do but I thought I would ask here as well about anything that is super important with respect to the quality of the interior build.... cabinets, insulation floor, roof and walls etc...

I don't know anything about custom builds and I want to try to get as educated as I can about what needs to be done for a quality build on a van.

if you have suggestions.... please tell me. I'd appreciate the help.
I am not going to do anything till I have a good understanding of what needs to be done.

thanks