They already said Firelands is the next raid. They said also that CoT: BotA is coming around 4.2ish. Then I bet we will roll into Deathwing after that. As for the entrance for DWL. I believe it's inside the instance Grim Batrol. There is a locked gate just before the last boss with draginkin fighting behind it. That is were I believe Deathwing is at. (much like MC was inside Blackrock Depths.)