With everything in flux, this seems as good a time as any to make this suggestion. I think it would make a lot more sense to move one of the portals up to Hilm castle. Specifically, the portal from Arnax. After all, practically speaking, Center and Arnax are literally two transitions apart. Losing the Arnax portal would add a little time for some destinations, but moving the portal to Hilm would save a LOT of time when going up to the Great Forest, The Deep, etc.
Certainly, this portal shift could be tied into a plotline, so the players would have to earn this transition. Before that, though, what do others think of this possibility?