For the departure around 6:30 p.m., you probably want to use the parking lot on Harbor Drive, but keep in mind you'll need some way of gaining some height in order to be able to photograph over the fence. Using a step ladder or standing in the back of a truck would be ideal: you'd be able to get an image similar to the following: View Large View Medium
Photo © Cheuk Man Kevin Ho
If you don't mind photographing the 727 after it's already airborne, you might be able to stake out a spot west of the terminals and the construction.
You might keep an eye on the flight trackers and try to photograph it on a day when it comes in late. Normal arrival is around 8 a.m. if I'm not mistaken.