Reno -> San Francisco

Hi,

we're doing a short trip to the USA at the end of November. Out trip
starts in LA, goes over Las Vegas and Reno to San Francisco and back
home. It's our 7th time in LA and Vegas. We also know the horror of
miles between Las Vegas and Reno, but we don't know the area between
Reno and SF above the highway which links both citys.
We got three days for it (Reno - SF). Is there anything interesting
to visit? How about Sacramento? Never been there. We also thought
about staying a little longer in Reno for doing some day trips.
There's no reason to stay in SF, because we've been in SF several
times. So, is there a must see between Reno and SF. I know there is a
Six Flags park :-). We like shopping, but we also like nature. All
suggestions welcome.

Thank you
Roland
Germany