Iride01 

If you are going to be off the bike long, consider a trainer or stationary bike. You can put a comfy saddle on it and sit very upright keeping without needing your arms on the bars. All the while spinning the cranks to maintain your cadence and keep your heart pumping the higher HR that it needs to keep your aerobic training. If you use your road bike in the trainer, you might need to slide the saddle all the way back to be able to sit comfortably upright and pedal with no hands.

For the few times I'll get on a trainer or stationary bike, I find that watching cyclocross races or other cycling races on youTube seem to keep my mind off the monotony of going nowhere.