Hello Marge,
Since I am part of a five-generation Napa Valley I think I might be able to help with your request.
A unique experience:
http://www.castellodiamorosa.com/ The best chardonnay:
www.rombauer.com/‎Francis Ford Coppola’s Winery:
www.inglenook.com/‎ Francis has finally been able to put the former exquisite Inglenook Winery back to its original grandeur. I had the privilege of working for Francis until I retired. Be sure to taste the Cask Cab and the Pennino Zin. Both wines are to die for.
My cousin’s winery:
www.caymus.com/‎ You will have to phone and make an appointment to taste.
Fun and good wine:
www.plumpjackwinery.com/‎I am not familiar with Hewitt. It seems that wineries change names often in the Valley. These are the wineries I take visitors. Hope it helps. I just realized I will be in the New England area will you are in the Napa Valley. Enjoy your trip.