Do you want speed or scenery? What time of the year are you leaving? And what are you driving/towing? What did the Trip Planner say was the shortest vs. the fastest route? All of these factors enter into determining the best route.
If I were in a hurry, I wouldn't go through the mountains northeast of Phoenix, I would just stay on the all-Interstate route. If I had plenty of time and wanted to see some very picturesque country, I would take the US and Arizona highways.
If I were traveling during "iffy" spring weather, I might chose to stay on I-10 to I-25 and then head north to I-40. I-40 between Flagstaff and Gallup can have very high winds, and even snow, in spring. I have been in Gallup when I-40 closed at the Arizona state line due to early April winds. Of course, I have also had to stop and camp overnight on I-40 in Oklahoma because the west winds were so strong that I was having difficulty towing my travel trailer back to Colorado.
So, you now have a lot of factors to consider!
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2016 Rockwood Signature Ultra Lite 8244WS 5th Wheel; 2015 Ram 2500 4x4 CC-SB 6.7L CTD
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