Well, this is interesting. I'd love for this to mean something big like Indiana Jones but I'm not going to get excited yet.
The tree house is the only existing attraction over there I could see them messing with. Is there any undeveloped land in that vicinity that wouldn't require significant work be done on the railroad and/or Caribbean Way?
I know there is path going back stage there but it doesn't seem like there is a ton of land unless you are talking about the pad on the other side of the railroad tracks and Caribbean Way or stacking something on top of PotC.