I hate that golf is so big in some fields for networking. I actually took lessons over the summer to be able to (theoretically) participate in stuff like this. I’d need a lot more to be a proficient golfer. (The park district offers relatively inexpensive lessons, FYI, if that’s something you’d ever want to consider.)
Anyway, unless this would somehow make or break the relationship or deal, I’d pass. Your travel plans are set. December is a very busy month for many people and it’s already Friday — our weekends are already mostly booked up through the end of the month. I don’t think it makes you not a team player to say no to something that has come up last minute after plans are set during what I’d argue is the most hectic month of the year… especially if you already have a track record for being a team player, one “no” shouldn’t be a big deal.