Thanks!
Today I learned about motion planning grids and coding paths in GML. Most of my time was spent troubleshooting. Had some difficulty getting the path to be visible so I could see where points were being added. Novice tip: put draw functions in draw events :')
I wanted to be able to demo what I'm up to, so I'm exporting to HTML5 as I go. Yet more time troubleshooting to get the game to not crash before it even loads the room. But all is well by now. Feel free to check out the "playable" snapshot on the page that I use for testing it. Spacebar restarts the room and generates a new level. The path and grid lines are a bit distracting, they're just for my own reference. Watch that hedgehog go!