There are early buses for the Character Breakfasts, just give yourself plenty of time because they do not run as frequently as they do when the parks are open. I would be at the bus stop at the POP no later than 7:15
The buses generally goes to the MK park, sometimes though people have stated that the bus driver has dropped them off at the CR if the bus is not crowded. When we stayed at the POFQ, the driver would not stop at the CR because the rest of the bus occupants were going to the MK. It can not hurt to ask.
Otherwise if you are dropped off at the MK it is an easy walk over to the CR.