Don't use TMC tiles in a LttP game. It will never work. Trust me, I know. I tried it.
Not having access to my spritesheets until the weekend, I can't GIVE you anything. I can give you some ideas you could use.
Like a TREE! The tree at the lumberjacks house in ALttP could be used. You could burn it or bomb it or something, to get an entrance to the dungeon. That's just my idea. You could always just have a temple or something.