Winery wedding

Your website is the best for this. Just add a card with additional information and make sure this is here. I’ll suggest maybe having transportation if your budget allows it or special rates on Uber for all guest is always appreciated it.

I would certainly let it be known sooner rather than later: on the invite and website, word of mouth, etc.

I would put something on the website indicating that the nearest hotel is x miles away. I don't know if you necessarily need to warn adults of the dangers of drinking and driving. People who do it aren't usually doing so because they are ignorant of the dangers.

If it's in the budget, maybe you can arrange for a shuttle for your guests

How far is the nearest hotel? Are there ubers in the area? Is it in budget to provide transportation?

You have to trust adults to be adults. I would look into local taxi services and provide those phone numbers somewhere in your venue. At the gift table? Printed and taped to the bathroom stalls? something like that.