Must see/do things in the the area during my visit

Hi all, I’m from Chicago and visiting some family that lives near Lake Wildwood for about a week.

During that time I’ll likely have a day or two to myself with access to a car. I was wondering what are some must see/do things in the area or within a day trip of Grass Valley? Assume Lake Tahoe is on the list, but wondering what else?

Really love hiking and checking out antique/thrift shops.