[quote=@Vertigo]
Sorry to double post, but! From what Fellwing saw in her vision's bird-eye view, would going to the stronghold be a quick trip or a sizeable detour (or something in between)?
[/quote]

Don't worry about it!

It's not a huge detour, but it's not quick either. In fact, the cave you're in is closer to the center of the island than it is to the stronghold.