The wineries are definitely in the business of selling you wine. But if you don't like it, that's cool too.
Some have cheese, some don't. Eat between, don't expect to picnic.
Do NOT. Under ANY circumstances. Drive while intoxicated. I’m very serious. Aside from the legal implications should you be pulled over and caught (A DUI fine of $10,000 among other ramifications), it is just downright stupid. Remember, it’s not just you that you have to worry about - it’s everyone else. While you may have had only 2 glasses of wine and feel fine, there’s a good chance there are others on the road who have had more. Hire a driver, designate a sober friend, get an uber. There are OPTIONS.
The Mayacamas Range is laden with some pretty gnarly roads. Hair-pin turns, narrow, gravelly roads, cliff edges - it’s a challenge for even the savviest of drivers. You will want to give yourself PLENTY of time to get up there if you want to arrive on time with your breakfast still in your stomach. Definitely hire a driver if you don’t plan on spitting, you will not want to navigate that road with even 1 glass of wine in your system. Also, because service is spotty don’t rely upon uber to come pick you up and it is illegal for them to wait for you.
Howell Mountain and the rest of the Vaca Range is slightly more civilized than the Mayacamas Range, but you should still proceed with caution.
While this will always be dependent upon traffic, these are your drive estimates:
Downtown Napa (Oxbow) - Calistoga (Main Town): 45 min
Downtown Napa - St. Helena: 30 min
Downtown Napa - Rutherford: 25 min
Downtown Napa - Oakville: 20 min
Downtown Napa - Yountville: 15 min