I like where you are going with it, and would advise that you keep going.
It has been a while since I have used AutoCAD to any useful effect (moved to Inventor several years ago), but I was able to open your file and turn off some of the layers to get a better idea of what you have going on. (I did have some trouble viewing because the cube settings were oriented with the curb side set as the top and I couldn't figure out how to change the read only default.)
The profile has a decent look to it. Some people prefer to have the front radius come down and hide the hard edge of the trailer frame, whereas you have the front radius ending at the top front edge of the frame. A tongue box will break this up, but just saying, it might be something you want to consider if you haven't already (now would be the time to change it).
The other thing is, with the modeling software you have the opportunity to work out all of the details on how you are going to fit you bulkhead, roof spars, door seals, hatch, hatch seals and many other details. I would do all of that now. The more things you work out to the last detail now, the less things will bite you later after "painting" yourself into the proverbial corner. Many times during my build when I have had a material shortage or weather holdups I have been able to do work on seemingly unrelated things and keep busy because I had fully modeled most of the details. This allowed me to work dimensionally to a plan without having to worry about things fitting together later (... at least I didn't have to worry too much
).
Finally, the upper rear cabinet looks like a box that ends before the ceiling. I would encourage you to think of the cabinetry more like integrated structural elements of the whole cabin, rather than components that get put in place after the cabin is built. Run the face frame up to the ceiling and utilize that small wedge of space you currently show over the cabinet to increase the volume inside the cabinet (unless you had planned on this being an electrical chase, or something like that).
AlmostTD.dwg