Wear a pair of jeans, pack one pair, (or other trousers.)
Bring a clean T-shirt for every day, 2 sweaters, one fleece jacket and a wind and waterproof outer coat.
Wear mountain boots or other shoes you can walk on all day, every day and pack a second pair, (if only slippers for bathroom and emergency use.) And clean socks, making sure you have a dry spare pair with you at all times.
If the weather is already likely to be very cold, bring long sleeved T-shirts and long johns on top of above, or pajama pants, leggings or thin training trousers (two each will be enough). And mittens, shawl and woolly hat.
Your toilet bag with just the essentials, comb, toothpaste and brush, shampoo, soap and deodorant. These can be in small travel containers, as you will not need more than 100 ml or one oz for 5 days.
A small towel can be useful and if you share bedrooms, pajama.
Do not forget to bring your camera, with spare batteries and/or charger, and spare memory cards or extra film.
A guidebook and a basic language guide so you can 'talk' with the local people if needed.
If you feel the need, your telephone, personal music player, list of addresses for postcards and a diary to make notes on the trip.
Above is twice as much (or more) than I plan to take on a 16 day holiday to eastern USA, with like climate conditions. I have learned to leave home with a daypack only.