I also prefer having the tube and fully understand your question.
In my experience the tube freezes mostly on the backpacking trips during the morning and evening hours (except when I am in very cold or extreme altitudes). With that said, for the most part I am able to use it during the day.
As I climbed bigger mountains I was struggling with the bring--don't bring question. So I recently switched to a new system.
I bought a small light weight (1 liter-34 oz) platypus that has a cap and a tube. I take that plus my two naglene bottles. In this I can pour water into it and use it if if the weather permits but I still have the naglene as back-up. I can also use it for powered water and other drinks. Moreover, the weight is so light that even if it is inoperable, I am not concerned about the extra weight.
The interesting thing--on one very cold night I had placed a naglene bottle inside my backpack in my tent. I also had the platypus with some water in it and the cap on. In the morning the naglene was frozen solid. the platypus was also frozen but due to its flexibility I was able to break up some of the ice and free enough water to use while melting snow.
Final answer--My guess is given the day temps you will be fine but it is always a good idea to also have a small bottle of water as a back-up.
My two cents
Have fun!