As there's not a lot of discussion about the Gold Country (Sierra Foothills), you might start by reading these previous posts to give you an idea of what the area is like. Most towns are fairly small and don't have a year-round population to support much fine dining. I think it would be fair to say that most dining is informal and menus are pretty traditional, though there have been some exceptions reported here.
Sacramento hounds and other Central Valley hounds will probably have the best info for you as Placercille and nearby El Dorado is fairly close to their home turf. Hope you enjoy your trip! The serving wineries should also have some area recs.