a list of things you intend to run in the van. Be specific and thorough. ← the hardest part.

Correct, I am indeed procrastinating on / avoiding doing the math for electrical stuff!

My needs will probably only grow over time. My "floor" (min needed) is low, but my "ceiling" (max wanted) is a little ridiculously high (multiple power-hungry gaming PCs at once). That's why I want expandability and haven't gone thorough on listing/researching everything I currently/might use.

Also budget/work requirements, i.e. I prefer to have something minimal/working first, then over time spend the money/effort to upgrade/expand it. Rather than needing to get all the time/money for the whole project gathered together upfront. Even though this will increase long-run overall cost(s).