Actually we find the easier way is to get on 536 which will run you right staight into 417 untl you get to 528 which will take you straight out to the port There is much less traffic and it is much faster.
The easiest way to get on 536 from WDW property is to turn right onto 536 just past Bonnet Creek Resort. If you are coming from the other direction (Downtown) you'll need to either come across the Overpass Road or make a u-turn so you can take the right hand exit off of Buena Vista Drive.
Once on 536 keep straight onto 417 aka the Greenway then onto 528.
Here are the directions from
DCL website:
Take State Road 536 East which leads directly to the 417 (Greenway). State Road 417 is a toll road.
Follow the 417 to State Road 528 (Beachline Expressway). State Road 528 is a toll road.
Go east on State Road 528.
At the fork in the road, veer right to stay on State Road 528.
Continue on State Road 528 and make your way over the Indian River and Banana River.
Turn onto State Road 401, which will loop and head north over the channel locks.
Stay in the right-hand lane and follow the signs to Cruise Terminal A.
Once you are on 528 there will be signs for Port Canaveral. You won't be able to miss the ship at the port when you come over the bridges.
There are cash lanes on these toll roads, just make sure you get over to the right to stop and pay them. They are running about $1.25 now I think, and there are probably 3 or 4 of them. I don't pay too close attention to be honest. Just keep some ones and some quarters with you.