Implemented limited scrolling. The actual scrolling I wanted to do is broken, the 'ties' between the rectangles that identify what tile goes where are broken somehow. I don't have the infrastructure made enough to trace a dependancy tree to find out where/when they break, so it just regenerates the map each time.
Good enough for now.
Fixed the problem with the TiedRect approach I wanted to use, only to find it's decidedly slower than just regenerating the entire map every scroll increment... suprising, and likely not so decidedly once more map elements exist, but that's why you're supposed to test things out.]