Orlando driving is not big-city driving, and that route will not put you on an interstate highway. However, the main entrance to that mall is in a major traffic corridor with lots of badly-timed traffic lights and lot of lanes to cross to make your turns.
FWIW, the best way to get there so that you are not dealing with crazy traffic on 535 (and very confusing intersections involving long lights and service roads) is to go around the long way. It may take you an extra 20 minutes to go this route, but compared to the usual Saturday morning traffic on 535 there probably won't be much time difference, because although it is longer, this route gets very light traffic as a general rule.
The long route is: exit WDW property via World Center Drive, and then turn left on International Drive after you pass Caribe Royale resort; you will be heading north on Intl. Drive. You will then want to turn left again on Vineland Avenue, at the Regency Village shopping center (there is a Publix there). Proceed on Vineland until you see a McDonalds ahead on your right; that is your clue to get over to your left lane and prepare to turn left, as the entrance to the outlet mall is opposite the McDonalds on Vineland.
(This will also put you on the opposite end of the mall from the one where most tourists come in, so it may also be easier to find a parking space back there.)