There are some classic long established rides around here that locals have been doing on 25c tires (just like nearly everywhere there’s gravel riding) long before riding gravel became a style. Now though, with “road bikes” that take 1.8-2.25+ inch tires and 1:1 or better gearing so much more becomes accessible and fun.
San Miguel County is notorious for well maintained dirt roads that wind endlessly throughout the surrounding mesas. Some of the climbs on the course will hit 15%+ but a majority of the climbing will be a nice 6%-8%. So, bring your legs and your lungs and get ready because the beauty seems to increase exponentially as one climbs higher!