Make sure you are signed up for the Premium Outlets
VIP shopper. Then add both centers to your list and compare the VIP-only coupons/offers. These discounts are slightly higher than the coupon book you pick up from information, but can also differ from center to center even for the same stores.
If I am looking for something specific, I often check the VIP offers at Camarillo vs. Desert Hills. Have found several times where Desert Hills will have a better coupon - something like 25% off one item vs. $20 dollars off a $100 minimum spend at Off 5th. Then it becomes a question on whether the extra hour each way is worth it?
I visited San Marcos a couple weeks ago driving from San Antonio to Austin on a Saturday. 107 degrees and a million people. Our main focus was kids clothes as our 19 month old has outgrown most of his clothes. Did find a lot of value.