MK is the one park that it may be easier to take the bus. The bus drops you off close the the park entrance. If you drive you will park in the TTC lot, most likely you will need to ride a tram to get from the lot to the TTC. The stroller will have to be folded for the tram and depending on were in the row you are parked it can be a hike to the tram. From the tram you will have to walk to either the monorail or the ferry boat to get to the MK, the stroller need not be folded for these. Time wise the bus to MK is generally faster, especially it open since you only have to wait for the bus. If you drive, you wait at the toll plaza(no you don't pay, but still have to wait) follow the traffic into the lot, wait for a tram, walk to the monorail or ferry and then wait for that.
If you plan on going back for naps in the afternoon your car will be HOT, the bus is airconditioned.