I just found out there is a beach 5K near me on New Year's morning. I probably will do that. I've just kicked off my training for Boston, but since I'm self-coaching again this time around, I get to decide which local races I'll do. All the 5Ks I did leading up to New York turned out to be reasonably decent speedwork, not necessarily the absolute best way to prepare for a marathon, but a great balance between a targeted workout and plain fun.