So I started typing something up then I realised you know of two entrances to the tunnels the one in the cave you just came from and then the one In the battlefield which would you like to enter? It does matter btw
We know the tomb of Balin's father tunnels. We know the caves where we found Azgalan. I thought we had fully searched the second place. So I assume we are going to the first place. But I would be surprised if Balin's father was buried in the same place Azgalan use to hide his coffin, especially when Balin's father noted that they could never find the coffins. So I also have no idea where we're going. That's why I was suggesting Lord William might know where Azgalan had land holdings, long ago.