We recently spent part of an afternoon with friends at the Monte de Oro Winery in Temecula. They have a beautiful building surrounded by patios, both open and covered. They offer live entertainment, which was not too loud.
Their wines are very good and a sampling allows you to pick the wines you might wish to purchase. There is no pressure to buy and their staff are very knowledgeable and helpful.
They also offer food like sandwiches and a meat and cheese tray to go with the wine.