To do 20 miles a day for 5 days a week would be a tough row to hoe. My commute is 31 miles round-trip and even doing it as few as three times a week is very hard. For starters, commuting by bike means being up at 4 a.m., prepping the bike, and being out the door by 5 a.m. That doesn't include cooking or having any breakfast. The return trip is even worse yet for when I get home I have to re-pack the panniers with fresh clothes, wipe down/re-lube the bike, and charge my lights. I then have to cook dinner for myself. So by the time everything is completed its midnight and all I have time for is four hours of sleep. (really not enough)