Girona for 1 day

What I did was go to the main Tourist Information office by the river and ask for a free map and what to do. The employees were very helpful and pointed out historic sites and what to see.

http://www.girona.cat/turisme/eng/activitats.php

The large historic district houses what were for me the key sights: walkable wall, two cathedrals and a very good, not-too-large museum. Plus of course the streets of that area. It's great just for wandering around.

Thank you very much. Is there anything specific to check out in the Jewish neighborhood?

There may be. I didn't cover quite all of the historic district. I had planned to see the last bit and re-visit the museum when I swung back through Girona between Puigcerda and my final stop, in Barcelona. But the Sunday bus never arrived in Ripoll, so I spent the night there rather than in Girona.

I went to the Museum of Jewish History and took their guided tour (only offered once a day when I was there). It was given in both English and Castillian, so it took a while, but it was interesting.

If you have an interest in movies, the Museum of Cinema is quite different from most other such museums. It has extensive collections pertaining to the pre-history of movies, and on the three components that were combined to make them - still photography, persistence of vision toys, and projection lantern shows. The movies themselves are an afterthought here. I found it very interesting, but if daguerreotypes, zoetropes, and the like are not your thing, it won't be as much fun.

I enjoyed just walking around Girona. Alas, when I first visited in 1995, there were almost no other visitors; in 2015, there were lots of tour groups. They couldn't ruin it, but it wasn't as much fun as when it felt like my private discovery.