I think what you're talking about isn't a schedule, but rather somone's idea of the average time it takes to get from CSR to the various theme parks.
Buses for each destination run about every 15-20 minutes (well, at least that's the plan!), regardless of how long it takes to get there. There's no set schedule or time table, just expect that if you get to the stop just having missed your bus for a specific destination, it's likely you'll wait another 15-20 minutes for the next bus going to that destination.