Thought I'd provide a bit of an update. Still slow going because work has me tied up a lot and I've been dragging my feet getting population requirement checks integrated, but there's still progress.
Goof helped me get some extra polish done on the GUI, added a new system menu and implemented the medical center (doesn't do anything yet but it's there) and fixed a few mistakes I managed to make in the code. He also identified a possible issue with the population 'simulation' but that's something I'll want to worry about polishing later on, for now it produces the kind of numbers that work.
(http://i.imgur.com/pti1v5em.png) (http://imgur.com/pti1v5e) (http://i.imgur.com/Hru1nSom.png) (http://imgur.com/Hru1nSo) (http://i.imgur.com/tNyafqdm.png) (http://imgur.com/tNyafqd)
Screenshot 1: The new system menu.
Screenshot 2: The save/load UI as seen in Preview #1 only with external input disabled and the screen darkened to focus on the UI.
Screenshot 3: Colonist landers now required to bring down colonists. Don't wait too long or your colony ship will de-orbit and colonists remaining on board will die.