suggestions

My sister and I are going on a trip to Switzerland in about two weeks. We are flying into Zurich and have 11 free days before we fly back out. We will be staying in hostels, and will be couchsurfing. I have a few places in mind that I want to go: Interlaken, Berner Oberland, appenzell, Bern. I was wondering if anyone has any suggestions for some other areas to visit or fun things to do that wouldn’t be very expensive.

I am going to be vacationing in Biarritz this summer (end of July) for abour 4-5 days. After that I would like to go somewhere else for around 4-5 days. Originally I was looking into Bareclona and Madrid but someone told me the south of France is beautiful/interesting as well. I am definitely traveling on a small budget. This would be my first time in all of these places so I dont really know where I should go.

Any suggestions?