Lots of negative comments. I understand it's a big project.
I love traveling, this is my first step towards going on the road in the future.
Understood. I was actually young, once. :B
There were a lot of posts on this thread while I was typing so here are some follow-up ideas:
Forget about any schematic drawings or mechanical plans for your trailer. They wouldn't help and the advantage, as it is now, is that you can build out to your needs and wants.
You should make your own drawings and plans so that you can develop a schedule of installation. There will be no worse feeling than tearing down a panel to install a wire, later, for example. Drawings don't need to be CAD quality, draw on paper with a ruler, laying out beds, counter tops, plumbing fixtures, etc. You can even cut out small, scaled depictions and place them on a general depiction of the floor. A separate drawing for electrical. A separate drawing for plumbing.
You should know the GVWR of the trailer and understand that any weight added back in will have, as close as possible, distribution side-to-side. Also, the end result should have an imbalance of 12% of the total trailer weight to be carried at the tongue. Weight distribution can be important because if a DIY'er imbalances greatly to one side or doesn't allow for tongue weight, the result can be untowable.
It all may sound like a lot but if you can build a doghouse and put a light on it, you can restore a trailer.
Since you are new to trailer, and probably, house building, you may wish to get ahold of 3D building software that will aid in depicting possible floor plans. An alternative is to visit the MFG websites and see how they do it. Most have ample images and information.
