I'm one of the fortunate ones who lose little time biking vs. driving. Indeed, when I factor in the walk from the parking deck to my office vs. parking my bike right by the door, biking wins, and, as a result, I have very seldom driven to work. I do go multi-modal most mornings as that shaves a few minutes off the morning commute and gets me to work less sweaty. If you have a similar option, it might be worth looking in to.

Also, as has been alluded to, don't look at it as 2 extra hours each way, but, I'm guessing, around 1.5 hours each way because you have to figure that even without biking there's an unavoidable commute time. Also bicycle choice and riding style could factor in to your choices if time is a factor. Your estimate of 2 hours for 20 miles sounds about right to me, but if I actually had a 20 mile commute, I would be a lot more concerned about speed than I am now. I'd be looking at something a lot lighter and zippier than my 30+ pound touring bike for my commute. I feel like with practice and the right bike, you could get that time down to something more manageable, especially if you could figure other transportation options for part of the way.

Or, if it would be secure and wouldn't inconvenience you too much, your car could spend some nights at work, and you could do every other commute by bike. Drive to work, bike home, bike back in the morning, drive home the next day.