Here's a screenshot of what I've accomplished so far. It looks better than I'd anticipated!
Tomorrorow I'll implement heroes, so that will require subtiles, since the heroes will be traveling together. I'm not sure if I'll do the subtiles today or tomorrow - just have to see if I feel like working on this some more later on today! Should be pretty simple, since I'm not planning on doing anything like allowing different subtiles within the same tile to have different terrain. Just a 3x3 array or something!