Larger scale maps, and generating an island

[gerald]

Hi all, I'm trying to write my first module and am a bit stuck on map generation.

Ideally I'd want the map to operate similarly to Unreal World or Cataclysm: DDA, with the player walking on a large scale, mostly flat map with the map (and monsters) being generated as the player walks around. I could just load a really large map right off the bat, but that's wreaking havoc on my load times (also I'd like it to be scalable).

I'm also trying to figure out how to generate an island type of map, with a forest surrounded by beach/cliffs surrounded by water. Is such a thing feasible, or do I need to simplify majorly?