I made a little progress on this so I thought I'd post it. Stage 3 is proving to be a bit of a killer - the sloping sections result in an enormous image. The Stage 3 image attached is only half-done, there's another downhill slope still there, and already it's making my computer slow down to work on it.
More progress. The levels get somewhat more complex later on...
Here's the last of it. (Magica's castle is stage 7.)
They're up...though Donald seems to be missing from Stage 3, and the sprites look odd in Stage 5...
D'oh! I'll email you the fixes.