I think we can really psyche ourselves out worrying about upcoming trips like that.
In my experience, every time, when I was worried about drinking on an upcoming trip or at an upcoming event, it turned out to be no big deal. I came to conclude that fear itself is more triggering than the events, but one thing that helped me a lot is making plans - if I DO feel triggered at this event, what can I do, specifically? That helps calm the fears (you know you have tools to apply) even if you don't actually need to use them.