Absolutely necessary:
FFEF (or close) L12 clefairy on Blue

Decent timesave:
Extended chains (Dugtrio+Sandshrew, Pinsir+Tauros, (Tentacool+)Vulpix+Ponyta, Some combination of Seafoam pokes)

Minor timesave:
Water gun-less moon manip
Longer manips to save repels (Tentacool, safari pokes,mansion?, maybe seafoam?)
Pokeball manips (Saves money)

Magical christmas-land:
Moon manip with clefairy encounter