Great mod! This is really fun to use. Imagine what we can do once we can build bigger maps with a map editor! As for the edge crash problem, I think it's because ground units can't reach the edge of the map (it's always blocked with objects or impassability) so the game doesn't know what to do. However, airspeeders (Snowspeeders) can pass the map edge, and have their own movement class. I'd suggest making a variant with the speeder movement class and see if that does anything.