The only issue you would have with autotiling the walls and ground tiles right now is that there isn't a graphic for single-tiles. So the smallest patch of grass you can make is 4x4 tiles.
I’m working on an update that adds separate auto-tile sheets, it should come out when I release a new pack in the series!
But if you don’t wanna wait for that, it should be possible to format it to auto-tile if you have a good template and you don’t mind doing some copy and paste.