Re-read your last post. As you have kids I am not sure if I still go with my suggestion of HPF. Although very close to Hermanus harbour and having some fantastic wine, their tasting facility is a modern building in what could be described, unkindly, as a shopping complex. This includes the Wine Village store that macsym mentioned. The actual HPF vineyards are out of town (actually near Rakka) and are very much off the beaten track.
The best choice which is a full vineyard, and is open until 5 o'clock, is then Bouchard Finlayson. They have a lovely estate and wine tasting facility 10 mins further up the valley. They have a broader range of wines than Hamilton Russell next door and some new stars (try the Hannibal new Red Blend which blends French and Italian grapes and influences. They have a beautiful estate with lovely views. They are also open until 5.
For more detail see :