Itinerary help - 7 days in Switzerland

I am going to Switzerland in a week and I need help with itinerary. I am staying in Iterlaken for 5 nights and than one night in Zurich with a friend. I built an itinerary in the Iterlaken area including two days for mountain trips - a day for Jungfraujoch and a day for First and Grindelwald. But I have been checking the weather and it has been rainy for the past week and the forecast looks gloomy as well. So I'm wondering what can I do on the two days i planned to visit the mountains if the weather is as bad as they predict. Here is what I had planned:

Day 1- arrive in Zurich in the morning. Train to iterlaken with a stop in Bern to see the city.
Day 2 -Aareschlucht, Reichenbach Falls, Rosenlaui Gletscherschlucht, Gissebach Falls and Brienz.
Day 3-Jungfraujoch , Lauterbrunnen valley and Trümmelbach Falls
Day 4 - Thun, maybe Schloss Oberhofen, lake Oeschinensee, lake Blausee
Day 5 - First , Grindelwald and a trail on Shynige platte
Day 6 - Travel to Zurich with a stop in Lucern t tour the city.
Day 7 - Zurich and Rhein falls

thanks in advance.