I would recommend avoiding the 535 area and go to the exit that takes you to MK. That 535 area with Downtown Disney has a ton of lights and retail on either side and always has huge backups, especially in the afternoon for check-in time. If you get off the MK exit, you can go through the main entrance arch too.
I like going through the MK parking booth, off to the far right, you just tell them you're checking in and take the road to Fort Wilderness. You won't have to pay for parking. After you pass the Fort Wilderness entrance, you'll come to a light. At that light, turn right and you'll be on the road with POR and POFQ. For Old Key West, you'll turn left onto Vacation Way, then right into the OKW entrance.
It's a nice little ride to get you in the WDW mood. You see the main entrance, and lots of signs and billboards that will really make you feel like you're IN Disney World.