Just started on my build.
Requirements
Fit full size mattress between the wheel wells.
As much head room as possible and still fit in garage.
Bunk for two smaller children.
Bunk will take up most of what will be the gally for now, needs to be easily modified afterwards.
Insulated with AC and heating solutions.
Storage for miscellaneous camping gear.
We typically have electric and water at our sites, so the electrical system will be as minimal as possible.
We are on a mission to camp in every state park in Texas.
We have roughly 15 under our belts so far, but due to school and work, we have been limited on when we can go and the Texas heat tends to be unbearable a lot of those times.
I've started with a 1720 HF 4x8. Coated with Rust-Oleum bed liner. I've underslung the axle. And laid out the grid work for the base. Glued and screwed that frame together and worked out bolting it to the trailer using seven 3/8 carriage bolts with lock nuts and washers.
Next up is plywood flooring and undercoating to protect the base.