Print one from all boxes. There is one for all cards, one type in each row + spacer for Treasure cards (as there are less than Door cards). Check photos.

There is also one big box for your stuff or just use it as spacer.

EDIT - add sleeved version. Smallest part is for Portals, in front of these is space for Treasures and the rest is for Doors. Used 80 microns sleeves.