To pass those tombs you need the axe and its in level b2 you need to drop down from a room in b1 that has a chest that you must have the hookshot to reach.
When you "land" you should be in a room with a blue carpet.
Kill all enemies go right then down and I am pretty sure you are in the room with the axe now?
This route wont be open unless you have beaten him all 3 times in the crypt so there for I also missed it the first times I was going looking for it.
Let me know if it worked otherwise I will go looking again.
And that secret tomb is VERY close to the final geist.... it all up to you to figure out how close....