When my parents were here a few summers ago, we had dinner and toured Columbia Winery via the dinner train. It was actually a pretty nice ride and we were seated in a private dining car because of the size of our party. That made it seem more special, but sitting in the general area you also get the chance to meet other people on the train. The food was good (but not spectacular) and the wine tour was interesting.
All in all, I'd say it's a great way to spend an evening, but not something that was interesting enough to do all the time.
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