Hoy to optimize CP vs storage space in calpheon.
Ill add passage in the coments that was very helpfull too:
Right next to (west for, it is literally touching Calpheon) there is a place called "Gabino Farm". There is a lodging lvl5 (total of 8 workers) for 3 CP. That is the best one for Calpheon.
To unlock the room, you only need 3 CP, that will net you 8 storage for that price. So for 6 CP you get 8storage and 8lodging.
Hope this helped :)
Link to the reddit thread
Hope this helps.