I agree, pose and animate the dragon first in DS and bring into Bryce to get the starting camera position right.  Build your scene using very basic textures and unanimated water and sky.  They can be changed later.         

As we all know rendering animation can take a long time, even in preview, so hide the objects that you are not working on.  Ex.  if you are working on water movement, hide the dragon.

Can't wait to see your final!!