Hmmmmm......You will either eat in Flagstaff or Winslow Holbrook is just a nasty place, seriously. Pestos is good in flag, Crown Railroad in Flag, The Place in flag is great for breakfast. Winslow....hmmm....The fancy hotel there is supposed to be good, but I usually just drive right on through. They are doing work on I40 in Winslow and it makes getting around really freaking annoying, but it is part of route 66 so look around.
Painted desert and Petrified forest will be REALLY cold but most likely empty. If it has rained or snowed and the ground is wet you are in for amazing colors. Look for morning or afternoon light. As you drive east out of flagstaff look for an old route 66 tourist trap and turn off at Two Guns. Interesting modern ruins. The whole area around there is flat and arid but strangely pretty. Have a red, orange, and yellow green filter ready to go for BW. For color have an 81a and a polarizor in your arsenal.
North of Winslow is Homolovi State Park, an ancestral Hopi collection of ruins. Most of them are not reconstructed but the views of the hopi buttes are fantastic. It is a nice park (I excavated there one summer). Continue north of Homolovi and you have a small pull off for the little painted desert. A great undiscovered part of Arizona. It is a popular party place for folks heading back onto the Navajo Reservation so, think safety, and since it will be winter there will most likely not be anyone there. I have been ther three times this winter and I had the place all to myself. I live in N. AZ so any other questions just ask.