I haven't gone through a serious dungeon so I wouldn't know exactly. Like all Pokemon games you can probably assume that there will be lots of walking around in dark caves, however.

Battles? Steps? Open? You mean from town?

Oh, also. TMs can be used over and over again. Big plus. Super big. Now I don't feel like I have to save them up until I'm going to make a serious team. It makes the game so much more fun when you can actually use moves you want to.