Hey Mike,

If you're curious about what can be done
with symmetrical terrain have a look at this :

http://www.renderosity.com/viewed.ez?galleryid=115191&Start=1&Artist=audity&ByArtist=Yes

the stone walls, the entrance, the little pool
in the back, everything was modeled with the
terrain editor.

It's faster than doing it the "hard" way.
Create your object first as a bitmap, load
it in the editor, adjust it with the paint
tool, add erosion, cracks, stairs, etc...
and it's done !

Eric