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.