Advice needed: Winter One Bag for 2 weeks

Greetings. I am a black woman that needs to travel from Des Moines to Buffalo (by train). I’ll be in Buffalo with family & want some advice that will keep me from attempting to fashion my way into overpacking. If it helps: I’ll be traveling during the holidays; I’ll be using a 35L suitcase backpack (Tortuga), and I probably won’t be doing too much aside from knitting scarves or something. How does one do One Bag in the winter, staying prepped for the worst but hopeful for the best?? Thanks for your time and advice.