I'd say it'll take about 4 hours. My 20 mile commute to my girlfriend takes about 1.5 hours at least. Although, titanium bike, 4am=no traffic, little to no cargo, maybe a little over 3 hours if you hammer it.

I will say commuting 13-15 miles to school each way keep the road bike. I had a hybrid commuter bike and it sucked with added weight. I went from 8-10mph to 15-17mph when I made the switch. It saves me 20min/way.

I'd also build up to that distance. Maybe combine transportation methods or do half and half. I nearly died my first ever 7 mile ride on a mtb but now can do 26 miles no problem on a road bike.