This is an amazingly detailed 3dtopo of the Cathedral Lakes and Budd Lake Drainage. The file is so detailed that I cut it into 4 pieces and printed them out separately and you still aren't capturing all the detail.
The photo shows the prints with the lakes colored in with blue sharpie. Much easier than messing with a dual extruder print, and it looks better too.
It was made from a LIDAR dataset made available on http://opentopo.sdsc.edu/. The dataset is so detailed that you can see individual trees, but it needs to be severely decimated just to get part of it on your computer.