Plan is to build a 5x8 camper on the 4x8 HF trailer for me and the wife along with our toddler.
As I sit around hoping a HF nearby gets a trailer in stock this week

The base is inspired what ghcoe's #1, but with some added spacers to allow for a drip edge.
(Sorry my mock up skill are limited

Side View
Top view
Anything I'm missing for the base? Figured I was best served to do some extra planning while i wait for the trailer and flush out my BOM spreadsheet.