This will enclose the board, a 3000mAh battery, a power switch, and a GNSS unit. It's not perfect, but I've spent too much time on it already.

Requires some soldering for the switch and it's probably a good idea to use heat shrink over the leads.

The board and GNSS: https://www.amazon.com/dp/B0FRS36YQK
The battery: https://www.amazon.com/dp/B0FRMRQVNM (the board kit came with the right connector and I had to splice it with the one for this battery. there are others available that have the same dimensions as this one but with the correct Micro JST 1.25 connector)
The power switch: https://www.amazon.com/dp/B0BZHZDBBY
Wood screws: https://www.homedepot.com/p/Everbilt-4-x-3-4-in-Zinc-Plated-Phillips-Flat-Head-Wood-Screw-12-Pack-827871/317479605