I'd like to add a couple little things.
1. Retrieving arrows/bolts from zombies. They can't all be broken. Maybe have a chance to loot 1 or 2 from the body if the zombie is killed by one.
2. Someone mentioned rafts. But I was thinking of expanding on that a bit. Maybe a block that floats so you can build a sort of house boat? It would have it's advantages and disadvantages. Zombies can't swim, but you can't really do much farming on a boat.