We were there 2 years ago for the entire Thanksgiving week in our 24' C. Temps were in the mid to low thirties every day. Up until Thansgiving we could drive the entire park but then they restarted the shuttles for the rest of the holiday weekend. Some of the shuttle stops have parking that will easily accommodate a 25' C but certainly not all of them.
Bundle up as the canyon is usually very cold in late November. Coming in from Spingdale you will have no need to drive the tunnel. Watchman is definitely where you want to stay. Enjoy!
:C