Count Down for our Europe Adventure

We are one month away from our Adventure to Europe. I and my 2 children going to start our adventure in France, then heading
to Germany, Sweden, And Copenhagen. This trip is mainly to see all my friends that haven't seen for long time and also to explore new places.
I and the kids will couch-surf all the way and find our way across town. However always I get the same question What things to pack in our back-bag especially traveling alone with 2 kids? The rule of thumb that I found to be useful while traveling is to keep clothes to 5 pieces each.
5 pants/5 shirts/5 undies. Also just one extra sandals. Also, while traveling on airplane I wear layers of clothes.
It will keep me warm in the airplane. Since I am staying with friends I have access to washing machine. We do not check any back-bags, we carry everything with us. Each child has his own back-bag that includes their clothes and favorite books. Always the best part of traveling is the children learn so much about engaging with other travelers and not being glued to electronic devices.
We are ready for traveling. One Mother with 2 children, 4 countries......