Well, it's not an easy project, but any 2D game is possible with b4A.
First of all you'll need a game engine.
Download libGDX and play with the demos until you understand how it works.
Then, you should be able to move you player within an area, I would do the stages with tiled, defining a polygon for the walkable area, and if the clicked point is inside the polygon you can go to that point. If you need to avoid obstacles then you could use
steering behaviors library to move your player from point A to point B.
Then you should make a scripting system, as you want to have conversations with characters... I think it's a HUGE project, but interesting...