Rungs

Turn the top word into the bottom word, one letter at a time. Par is the shortest way through, and you have two rungs to spare.

• -Turn the top word into the bottom word, changing one letter at a time.
• -Every step has to be a real five-letter word, and only one letter may change: the other four stay where they are.
• -Par is the shortest way through, and you get two rungs more than that. Run out before you reach the bottom word and the puzzle is lost.
• -A word the list does not have is refused on the spot and costs you nothing. Only a word that is accepted takes a rung.
• -An undo takes the last rung back off the ladder and gives it back to you, so a rung you undo is not counted and never reaches your result. You get three of them.
• -Any ladder that reaches the bottom word inside the budget wins. It does not have to be the one par was measured on.
• -No hints. Both words are on the board from the first second, and par is the shortest ladder there is.

Where to start

Read the bottom word before you touch the top one, and count the letters that already agree: those are the ones you are keeping, and every other position has to change at least once. Work from whichever end has the fewer ways out. A word like STORK has two or three neighbours and CHASE has a dozen, so starting at the sparse end means fewer branches to be wrong about, and the middle is where the two halves meet. Trying a word costs nothing if it is not in the list, so guess freely: the only thing a rung buys is a word that was accepted, and the only way to waste one is to accept a word that leads nowhere. When a branch dries up, undo rather than spending your spare rungs climbing back by hand.