Getting to Kryst
The Quickest way to Kryst is through the portal found in Shoushi. There is also a Kryst portal in the Umbral Halls, however, unless you have a tie to the dungeon the quickest way to Umbral Halls is to run from Kryst. Before the portal opened in Shoushi, the quickest way to Kryst was via the Vesayen Isles portal near Bandit Castle.
Portal Connections
The Umbral Halls are just a few seconds from Kryst and there are portals to many towns within.