Ok, so in Cata, there's no more portals. I find this a royal pain in the derriere. Been questing in Mount Hyjal mostly, but for trainers/AH/etc you need to go to a major city. It seems Darnassus actually is the closest nearby. But when you then want to go to IF/SW, you either have to take a boat, or take the Dark Portal portal (they havent removed that... -yet-), and fly from Blasted Lands.
Yesterday i wanted to try out some instances, but you first have to "discover" them. I think in the end it took me 2 hours or so to discover 2 instances, mainly because of travel time and not really knowing where these things are. Pretty frustrating.
One thing i do know: move all your toons out of Dalaran before patch 4 or cata launches, or you'll have to sail them all out, at 15minutes a toon or so!