It's actually cheap enough and easy to do this trip by public transport, if you go to the port at sibulan and get the fast craft (p70 each way) then get on the Ceres bus to oslob which is maybe 30 mins ride.
If you want to swim with the Sharks being a foreigner it costs p1000 after a short seminar.
I'm sure you could also find someone there to take you to the waterfalls and the boulevard is also worth a visit.