Hi Kathy,
I think you have five options:
1) If you have a car, drive over.
2) Take a taxi. This will be very fast but will cost you about $10-15.
3) Take a WDW bus to the Studios (assuming you are going during park hours) and walk or take the boat over from the Studios. I would allow about an hour for this method, but it could take as little as 30-45 minutes.
4) Take a WDW bus to Epcot and walk through Epcot to the YC. This could also take between 30-60 minutes plus you will need to use a park admission to walk through Epcot.
5) Go to a park or DTD and change for a YC bus.
I can't think of any other options....
Good luck!
Bob