I've done a split stay many times. I have bell services transfer my luggage. Then I go out front and wait for the first theme park bus (except the one going to Epcot if I'm transferring to Epcot resorts). At that theme park, I just go to the bus stop for the new resort. Last time from AKV to BCV I took the bus to DHS, then the boat to YC/BC. The whole process took me 45 minutes.
We migrated from Disney transportation to car rental a few years ago. We still enjoy the boat rides and will take a bus to experience what we are missing but to get anywhere quickly without several stops, and to get from resort to resort, a car is the way to go.
Bill