Does anyone know where to get the warp pipe scrap to get to the crying toad? I can't find it.
You don't need the warp pipe scrap to reach Toad. You need to go to the first part of Hither Thither Hill (the area with the windmill) and go down the leftmost pipe in front of the mill (there are two). Once underground, go all the way to the right and up the pipe and you'll emerge next to Toad. Talk to him then lead him back through the underground (you'll have to kill any Buzzy Beetles on the way, or Toad will make a break for it). Leave the underground through the pipe (Toad will follow) and then leave 1-4 and escort him back to Decalburg. Then go see him in his house and he'll tell you a code: 'Forwon toothree'. Pick up a Fan from the Thing shop in Decalburg or 1-2 and sticker-ize it. Take it back to 1-4, if you have not done so already, and put it on the tree stump next to the windmill. It will open the mill. Go inside, and input the code, 4123, into the blocks. A pipe will appear. Head down it and do some platforming to reach the warp pipe scrap. Take it and place it on the missing section (down the pipe in the area outside the windmill, ie the one you didn't go down before) and go down it to fight the boss. Good luck!