Time to blog a bit!
I've finished the player area landscape bits. Regular landscaping tools wouldn't have done the trick, so it's all modeled geometry.
There are some obvious seaming-issues to address; I textured the bit that goes into the grotto before I'd come to a solution for all of it.
Basically it's all one big piece of geometry that's been cut apart and then reassembled as separate meshes in engine, to make texturing easier and so that the engine won't render the entire object when only a fraction of it is visible.
Now is a good time to talk about my texturing process too. Initially I wanted to texture using watercolours, but with some more thought realised it seemed unfeasible within the time frame, and it wouldn't provide me with the richness of colour which I wanted. Instead, I purchased a set of brushes for photoshop which emulate the look of watercolours really well.
They are the Ultimate Real Watercolors by Kyle T Webster and they are really amazing. Nothing beats the real thing, but as far as emulating it goes, this set does it really well.