Technically there is a way to go outside of the map and get to it. But it's literally just a copy and pasted chest from one of the other sides. It's not important.
You should be able to choose between getting the money or getting the class.
You have to complete the Crisis in Summeredege quest line first. To unlock Summeredge without any restrictions. Then go to the innkeeper and you'll get a mysterious note. That will kickoff events to meeting Carys. If you search through this thread, with the search bar, look for the walkthrough, for game version 4.6, by Redknight that I posted a mega link to. That should help with any questions related to quests.
Are you a male character? Only happens if you're a guy. You meet them, the "Flowers" of Geli, in Murkhal's tower, and free them while getting the sword with Lankin. You can then meet them later in Slinsk, in Act 3, and help them get back to their island.