Just tell Bell Services at ASM that you want your luggage transferred to OKW. They will take it from you and you can call OKW Bell Services to have it delivered to your OKW room later in the day. It generally takes most of the day to get the luggage transferred, so don't pack anything you might need during the day.
You could also choose to take a cab from ASM to OKW - expect to pay $12-$15, including tip for the taxi.
No way do you want to haul luggage on the buses - not even sure if the drivers will let you on the bus with lots of stuff - it could be a safety hazard to others.. You probably already know that there isn't direct bus service between resorts. That means you would have to transfer at one of the major parks or at Downtown Disney. What fun that would be - NOT! LOL
Best wishe s-