Order Turret Control right away, because you're going to be ambushed. After about 20 minutes of building up your forces, the Rebels stop coming. Take the first two bunkers, and hole up for a while. Oh, and AT-AA are critical for this mission, you'll need about 8 of them. I heard that it was easier to just kill all the Rebels, and then zip Dellis around on a Speeder Bike.