calico - I haven't had any problems with the camera other than finding myself inside a massive displacement.
virex - cool experiments - yes patch size seems to help a lot. But rather than pushing up the displacement value, I've found better results by using a really low displacement value in the hidden terrain and pushing up the buoyancy from variation, and clumping of variation values. I still can't get anything to complete a render in this program over 1200 by 1000 though, no matter what kind of landscape it is. Here's hoping the full release version will solve that.
Your results look promising, given that there's a whole planet of it, might be worth exploring to see what interesting forms are lurking a few thousand kilometers away?