The Contemporary is the first monorail stop after the MK, so that ride really only takes a couple of minutes and you are dropped off within sight of Chef Mickey's. It is the bus ride to the MK that is the part harder to plan. See if the front desk of your resort can give you an actual time when the bus will be there to make it a little easier to figure out, but in any case allot yourself a good amount of time (I'd say an hour at least before your ADR) for catching and riding the bus.
Have a great time at Chef Mickey's. We were there Monday morning and we loved it, it was just magical for my son!