On Rhen Var - Harbor...
ONLY ONE THING MATTERS...no matter which side you play as...TAKE THE LIGHTHOUSE!
As the rebels it allows you to create a kill zone in the entrance to the harbor...as the empire it gives you the ability to direct suppressing fire against the Fortress on the far side of the bottleneck. Forget the ice caves until you've been fighting to hold the lighthouse for a while. I've tried to cut off the ATATs by taking the ruins where the empire starts out...and it doesn't work..because by then they've taken the lighthouse and have two ATATs on the field of battle - your forces die by the dozens!
You'll find many of the truths we cling to depend greatly on our point of view -Obi-Wan Kenobi