In reply to zimpara:
The obvious one would be to do Avalanche/RedWall/Longlands on Lliwedd, and then continue round to the top of Snowdon.
Alternatively, something like a route in Dinas Mot (The Cracks, or Diagonal maybe, then continuing up Slow-Ledge Climb), followed by going round to Cyrn Las to do Main Wall, and then from the top of that either, perhaps, up to Crib Goch to do Reade's Route and then round the horseshoe, or round to Cloggy to do, say, Great/Bow Slab and then to Snowdon's top.