The way we handle the MK bus from the BC depot is to see how big the crowd is when we walk up. If the crowd is huge, then we walk to YC. You also need to make sure that you can get to the YC before the next MK arrives.
If you want to walk to the YC bus stop after checking the line at the BC bus stop, then you should stay on that side of the resorts and walk in front of the convention center. I think it is quicker.
Most of the time we just wait at the BC because they often send an empty bus right after the full one. If rope drop is super important than plan to be at the bus depot at least 45 minutes early.
The MK bus is usually fine if you are leaving a little later in the morning, like 10 am.