Dumbell,

In short. If you can walk that distance without symptoms then cycling should be fine - though avoiding crashing. To be very conservative trial flat ground or stationary bike for a few times and gradually build time on to resemble your ride to work. Possibly avoid very high gears or steep inclines for a few weeks until your endurance has returned and then ease slowly into them. Otherwise I don't see any reason for not including cycling into your rehab - though I cannot be 100% positive as you can appreciate. Latent and particularly night pain are the things to watch for and will guide your cycling/rehab.

Good luck