Wow, thanks Frank.
I actually forgot those missing tiles on the house...and they're pretty important tiles too.
As for the tunnel, they're supposed to go one tile higher, like so:
I got rid of the black on that one tile anyways, though.
For the trees, the tiles you are looking for are right here:
I also got rid of the grass for the trees, thanks for the heads up.
I've also attached version 2.0 of the tileset, this one's pretty much final. If anyone wants to play with it more, go ahead.
Thanks again for all your help, Frank