E-ZPass is accepted on 417 between the airport and I-Drive. As long as you get off at the I-Drive exit, which runs into Epcot Center Drive, you'll be OK. If you stay on 417 to the MK or AK/DHS exit, you'll hit either a toll plaza or an exit toll that does not take E-ZPass, and may require exact change. Once you get onto WDW property, you can easily get to any park or resort no matter how you entered.
Remember, toll points that are primarily E-Pass accept E-ZPass; those that are SunPass do not (even though E-Pass may be on the signs in smaller letters.) I think there are also signs along the road that say something like "E-ZPass not accepted beyond this point."
All mainline toll plazas are attended. Exit toll plazas are not and require exact change.