To the "how fer" question, for last night's interval workout I have to answer "only 11 miles." But I averaged 18 mph solo on rolling hills (actually eight times around a 1.4 mile loop that includes two short climbs and descents).
If there were a thread asking how many times I got my heart rate to spike at or near its max, I could proudly say "fifteen!"
Tonight I plan to go 22 miles with a group, flat terrain and 20-ish mph.