Actually, that is what I did to begin with using Chrome to Phone. But, IIRC, I could not access those maps in the middle of nowhere CO. After two days of experimenting that way, I jotted down destinations along the route.
For instance, this was one of my loops. I stayed a couple nights in Estes Park.
I recall having troubles accessing the map from Idylwilde, CO. We missed a turn and ended up going thru Fort Collins which worked out well enough.