Thanks! I guess one of the benefits of having no idea what you're doing is that you come up with interesting ways to get things done. For me, this is my first attempt at something that resembles pixel art so I went as small as possible to keep it simple. The idea being to build the scene up with small blocks as opposed to drawing larger areas with pixels (which I'm terrible at).
I blew up the tiles so they are easier to see, but the actual size in GameMaker is just 4x4 pixels per tile: 
I'm very happy with how it came out.