I have a much desired ADR at 'Ohana my first day at WDW. The problem is my flight arrives in Orlando at 2:52 pm, and the ADR is for 6:20 pm. We are staying at CSR, which means travel by bus, as well as the monorail. Can I make this happen????????
You'll need to be ready to check in, change or be ready to roll, and get to the bus stop fairly quickly, but assuming your flight lands on time, you'll make it.
If your flight lands at 3:00 I would expect to be at the CSR around 4:10, 4:15 that should give you ample time to get the bus to the MK and then either take the boat or the monorail over to the Poly.
If your flight is delayed or you find yourself running late, I would just grab a cab from the CSR and go right to the Poly, it would be less stressful.