We have four non-skiers traveling to Grindelwald for a weekend in early March. We only have two days as our daughter is in a semester abroad program in London. We arrive in Grindelwald around 3:00 PM on a Friday and need to be back at Zurich airport by 5:00 PM Sunday. Any suggestions on how best to maximize this stay. We are considering one day up to First and then sledging and another day up to Schilthorn.