When the mine elevator looks broken
The mountain elevator remembers checkpoint floors, not the exact spot where you turned around. Pick a five-floor target before leaving the farm and you can make permanent progress even on a short trip.
Find the mountain entrance
Walk northeast from the mountain lake to the timber-framed opening in the rock. In a new save the path is blocked until Spring 5 of Year 1. On your first visit, meet Marlon and take the sword; the entrance ladder leads into the working floors. A locked door out in the desert belongs to a different dungeon and will not start this route.
Reach a multiple of five before returning
Take ladders until the floor counter reaches 5. The elevator can now take you back to that checkpoint from the lobby. If you leave on 8, the next trip starts from 5; reaching 10 adds a second destination. Use this arithmetic when deciding whether to spend your last food: a fresh floor 6 run does not require risking your health to protect a checkpoint already unlocked.
Find the next ladder when the map changes
Look for an existing ladder before swinging the pickaxe. Break nearby rocks or defeat enemies to expose an exit on ordinary floors. On an infested floor, track down the remaining enemies, including anything approaching from a dark corner. Keep the ladder you entered by separate in your mind: using the upward exit ends the current descent. Random layouts can change even though the elevator destinations remain.