My commute is 9 miles but during the school year it's tough to get my daughter on the bus and make it to work in decent time. I'm fortunate that I don't punch a clock so as long as I arrive between 8:00-8:30 I'm fine. In order to still ride, I do a partial commute. I drive the worst part of my route (near my house) and park my van in a safe place then ride the remaining 5 miles. It cuts my commute in half, gets me to work on time and I don't have to leave early in order to pick my daughter up on time. I still get exercise and I cut my gas use in half, it's a win-win.
Maybe you could do the same, on days you just can't take the time to do the full commute, drive the huge hill and park half way to work and ride the rest.