OP do you have family obligations and such? That's the main reason why I only do my 31 mile RT twice a week. 31 miles RT takes me about 2:15-2:20 total time. I was splitting it up between days on Tues-Fri but that meant leaving my car at work twice a week and also keeping the bike rack on the car all week long. Last week I did the whole round trip in a single day, on Tues/Thurs. However those days meant I was gone from the house, my wife and 3 y.o. son for a whopping 12 hours (before 6:30 am to almost 6:30 pm). But my car stayed at home and I didn't have to use the 50-lb. bike rack at all, which was nice.
I couldn't imagine riding any farther than that for a round trip. But my commute is also quite hilly and I never can break 14 MPH moving average unless I have a healthy tail wind in the afternoon.