I've lived in Bend since 1995 and have traveled both routes many times. On Hwy 20 you are in high desert across the route, gas is limited with only one option between Burns, OR and Bend. Grades are relatively gentle with long flat or false flat sections. Some may view the terrain boring however if you get out and explore just a little the magic of the desert opens up. The Hwy 26 route is more forested and more small mountains. I find Hwy 26 more interesting, it is a touch longer. There are more scenic destinations close to Hwy 26. Weather is highly variable in October. I have seen single digits at night in the first week of October however that is uncommon. Typically October in between Bend and Boise will be nice days with daytime temps 50-70 and nights 20-50 degrees. Relatively low chance of precipitation. If you are spending time in Bend the website Bend Oregon Visitor Bureau for Hotels, Lodging or Restaurants
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