My commute is just under 15 miles one way. Not any real hills on the way there, until I am less than half a mile from the school. On the way home I have 2 hills, one being my street, which is a major climb (10-15%). I am thinking of taking another, longer route on the way home that would eliminate the hill before the one on my street, which would make the way home about 17.3 miles.
I do the commute in anywhere from 57 minutes to one hour 3 minutes. I don't try to go fast, especially in the AM. If i go slowly and eat before and after I ride in, it's fine. The ride home never bothers me; I'm going home!