Can't help with the wife issue. I can offer a few tips from a design prespective:
Symterical layouts are boring, allows the eye to be lazy.
Create visual intrest by changing the height of the rocks, one side higher than the other for example.
Use an area, offset from center with no rock.
The cave is a good idea, offset it though form the center, also don't use two, kinda like the symetry thing, odd numbers are more interesting.