As for gearing and going long (80 miles or more), I'm sometimes in the big ring and sometimes in the small. I have zero idea what the recommendations are, but I've learned as I go that if I can keep my cadence between 85-95 and my heart rate below 155, preferably in the 140s, I can seemingly ride forever and feel good the next day. I also mostly ride in the flatlands along the ocean, and almost always with wind.