Nice box. I think either a simple build and trying for similar wood tone on the neck - or a banged up old relic look with a lot of soul. Nothing fancy or flashy. Do what the box tells you. Set it aside until you kind of know what to do.
I can visualize a great build out of that box. Then again, I visualize whirled peas. Love the look of it and the relic hiding inside.
Fingerboard level with the cross piece, put the bridge on top of the bottom cross piece and tuck a mag pup against the top one. Weather the neck and box, it will make a great "vintage" build that you can develop a good "history" for.