Find Toad beneath the Fishing Hut
Enter the Chalet and clear the ghosts before inspecting the monitor. Take the Smokehouse route: restore its missing scarf with Dark-Light, then pull both scarves to open the gem compartment. At the Basin, restore the Fishing Hut door. Inside, vacuum the snow and take the sapphire beneath the left-hand boards before freeing Toad. Use Dark-Light on his painting. The floor breaks and drops both of you Under the Ice; this fall is part of the route.
Escort Toad back through the mine
Ride the rising air to the upper ledge, carry Toad and launch him into the narrow rear shaft for the sapphire. Proceed through the Terminal and use the Airway route to obtain the keys needed to return. Launch Toad to ledges he cannot reach, and carry him over fragile ice instead of putting both characters’ weight on it. Back at the Terminal, pull the false covering off the mirror and restore the missing barrel beside the reflected door for the Boo. Clear the Basin ambush, retighten the Airway bridge and bring Toad to the Chalet Pixelator. The High Wires bird’s nest and the Airway telescope-and-barrel puzzle provide two further gems on this route.
Collectible checklist
Secret Mine gems — #1 Smokehouse, #2 Fishing Hut, #3 Under the Ice, #4 High Wires, #5 Airway
Boo checklist — Terminal: After obtaining the Airway key, return to the Terminal. Pull the false covering from the mirror and restore the missing barrel beside the reflected door.