Good. Some suggestions for tuning

1) Get on more hikings on Zion. Best views are seen from trails. You can stay at Kanab this day instead of Page if tired.
2) You likely need more than 2 hrs in Monument Valley if you drive inside (recommended)
3) Load some food/water from Safeway, Page before Christmas eve
4) You seems to have time on 12/25 to visit Natural Bridge NP as well.
5) You may not need a whole day to cover Deadhorse Point SP and Island in the Sky. So you may be able to get on Byway-128 or Arches the same day.

Have fun and a safe trip!