Hi and welcome to the DIS!
The actual ride time is about 10-15 minutes, but you should always allow 45-60 minutes to get from point to point using WDW transportation. You could make it in less than that, but 45-60 minutes accounts for walking from your room to the bus stop, making other stops along the bus route and allowing people to get on and off the bus, riding to the park, then walking to the entrance from the park's bus stop and getting through the turnstiles.