how to travel switzerland as a first time goer.

hi guys, im planning on travelling switzerland this july hopefully. i feel a bit overwhelmed about formulating a comprehensive and correct itinerary and was wondering if im going about it in the right way, or if it needs changing or tweaking.

ill be in switzerland for 9 days. friday 3rd july to sunday 12th july. ill be flying into zurich.

my plan is to use interlaken as my base

heres how it goes:

day 1 - arrive in zurich for 1200 hrs. train to interlaken and explore hohematte and interlaken, keeping the day light.

day 2 - trip to Lauterbrunnen and Wengen

day 3 - trip to Grindelwald

day 4 - Lake Brienz + Iseltwald

day 5 - Oeschinen Lake

day 6 - Mürren + Gimmelwald

day 7 - rest or one of the following:

Jungfraujoch?
Schynige Platte?
Harder Kulm?
Brienz boat cruise?

day 8 - Lucerne

day 9 - Zermatt (this is where i think im overdoing it. could leave it out for this trip?)

day 10 - back to Zurich for flight at 1600 hrs