I would take the bike but cycle for the time it would take you to walk there and back iyswim? So drop dc off then go for a 30 min cycle and head home. Or, go for a 30 min cycle then pick dc up and head home. So you are still using the time you would have used if you had walked, but you have the potential to get a better workout.
I have limited time to do exercise so I wondered between walking and cycling what would give me more of a workout. From home to day care is about a 20 minute walk or a 7 minute bike ride. There are no inclines it is all flat land. On the way home I have the baby on my bike which is an additional 10kgs for the bike ride home. What should I do to burn the calories and get rid of the extra weight. Help!!