While I agree that trying to get it right the first time is a "noble virtue", it should be born in mind that most of us are "works in progress". Thus it would follow that much of what we do is going to at some point undergo some revisions
It's for this reason that so much of design & engineering relies on some "standards" or "formulas" that they follow for what is called best practices. In the case of "one off's" the builder can shop for ideas to replicate and then fit the rest of the puzzle together with what is available to him or her.
As a kid I watched my Mom & Dad work on the "camper" as they called it. Dad had some ideas he brought to the table from his industry and Mom (who had studied "home economics") took charge of the basic layout borrowed from Kitchen Design. (the "U" shaped kitchen in particular)
Mom saw the rig's front seats as being all about travel. Behind them were the living space which she saw as being primarily accessed by the side doors. Here the "U" shaped layout (or standard) would be most efficient for the users of the rig.
The first rig didn't use a house battery. The starting battery was behind/below the drivers seat and easily doubled as a house battery. The rig didn't have a lot of house needs for electrical power. An auxiliary dome light with a switch by the side door jam and a reading light above the pillows of the bed provided all that was needed then.
Dad had ideas for an upcycled cabinet with a top that now featured a small sink and double burner stove. Inside was a 5 gallon plastic water jug and a box with propane cylinders. His design of the bed provided for plastic boxes for clothing etc that could slide out for access thru the back doors. ...or be pulled forward for access in the interior. He had a large plastic "foot locker" that sit beside the bed that could double as a seat when the fold up dining table on the cabinet was used. The Ice chest doubled as a seat for the other person.
They used this for some extended trips and long week ends. In time Dad built a rack on the roof and purchased a small aluminum boat and 9hp outboard motor for fishing and pleasure boating. When it was on the roof the Van looked like a high top.
But most of the accessing of the living space was done thru the side doors and the foot locker or ice chest could be moved out of the way to access the bed or crawl into the driver/passenger compartment. They bought a much later Van and retained the same layout in it. But they used and stayed with their original layout and I have too.
If you enter the rig from the side doors everything is to the left, right, or forward.
Same with an extended Van as I have now. But the extended provides room for a house battery under the drivers seat, a couple of
Jerry cans for water, and a full size bed. Again, the foot locker & ice chest can be moved around for convenience or travel.
that's a lot of wt. +Sloshing around
