Jul 2, 2018 - 9:46 AM
For a short duration like yours (I too did a similar trip last week), I would suggest you to focus on max. 2 places: Luzern and Bernese Oberland. Or better still, you can spend your entire time in the BO area. Luzern is a great city but if you had been to London, Paris or Amsterdam then you can skip Luzern. Just my thoughts.
In the BO area, stay in the Lauterbrunnen Valley for cheaper deals. I stayed in Murren but I really do not think one needs to stay in Murren or Wengen. You can always visit these places for the day and stay up till late evening. Lauterbrunnen is also more easily accessible (although Murren or Wengen are only another 30 mins away).
The Bond movie hotel is Piz Gloria at Schilthorn, where you can go directly from Stechelberg near Lauterbrunnen with 3 easy changes of cable cars. On the way down stop at Birg and Gimmelwald.
Grindelwald is a different location...large, very touristy, but great view of the Eiger. Again, it is an easy single train trip from Lauterbrunnen.
Shared bathrooms are not an issue at all. They are always clean and well maintained. Even public toilets are clean.