Best way from Thrifty to Epcot Resort area?

[cruise-o-matic]

Just booked Thrifty for our December Trip. $13.99 for an intermediate is hard to pass up, especially when economy and compacts were going for $12.99.

A) How quick is the shuttle to and from MCO (I am a Blue Chip member)?

B) Is it best to take 528 or the Ocseola Parkway? Our return flight is at 6:30 on Tuesday, so I want to make sure we don't run into any afternoon traffic.

Thanks.