I used a cobblestone hammer until I had materials for my end game hammer last world. It lets you clear out the stone, which you can use to repair it as you go. It's by no means the fastest method, but if you make a decent pick to accompany it, finding materials for your end game hammer doesn't take much effort if you focus on it.
If you're looking for something between that and end game, I second the bronze/steel option. Easy enough to acquire for repair if you don't RF or Moss it, while still having enough punch to get the job done. I usually rush a steel pick head for the mining level, then push through to the Nether for Cobalt for pick and hammer heads. Once you have that, you're sitting on the end game content of TiCo, so it's a pretty small push if you rush it with a plan.