Just got done with my first day of Gencon. I skipped yesterday. I am holding the quest compendium in my hands... It seems very nice. There is a quest from Kevin Wilson that requires EVERY expansion. A couple others require two, some one, and most just use the base game. The majority of them seem quite large as well. It was $30.
I also got an explanation of Sea of Blood from none other than Kevin Wilson himself. He's a nice guy, very approachable. We talked about Descent for a while. Anyway, Sea of Blood is essentially RtL on the sea. It doesn't require RtL, it's on its own along with base Descent. As far as I can tell it does NOT come with any new minis. No guarantee on that though.
The overland map is apparently from Runebound but I've never played that. There is a large island map and on the other side is an ocean map. The heroes have a ship that is upgradeable with cannons and other things. From time to time they land on islands and explore them. This is where the dungeons come in.
That's all I can think of for now. I snapped some pics of the game but they will have to wait until I get home.