Napa Tours

[PinotEnvy]

I'm going to have only an afternoon to visit a winery or 2 in the Napa region. Do any of you know about the Stonehedge Winery and their wines? They seem to have several varietals and they are closer in to SF, making them more convenient. Others near them are Rocca and HDV. Any comment or suggestions are appreciated. I've never been to Nappa. If there winds up being time for only one place, I want it to be worthwhile.

Thanks in advance.