I would suggest a bus to Hollywood Studios, and then a bus from there to WL.
You should allow 90 minutes.
That sounds like a long time, but anytime you are using 2 transport vehicles to get to a destination, total wait time can be up to 40 minutes. Add to that 15 minutes just to get out of CBR, depending on what stop you're starting from, as the resort has 7 stops and you never know whether wheelchairs will be involved.
From WL to MK, you have the choice of a non-stop bus (faster) or a boat (scenic).