We usually park in the Express lot ($10/day). A small shuttle bus picks you up and drops you off right at your vehicle. Some drivers jump out to help with bags. When the Express lot fills (which it often does) or when traveling in the winter with higher chances of bad weather, we opt for the Daily garage ($12/day). Covered parking to keep the snow/ice off. Large buses pick up/drop off on the ground floor. Not as quick getting to/from your vehicle as there Express lot.
Security lines usually aren't too bad. Lines for the A & B checkpoints aren't too far apart, so you can scope them out and pick the shorter line. Like china mom said, C is a bit of a walk and is only worth it if you're going out of a C gate or the lines at A & B are really long.
Besides Chick-fil-A, I also like BGR - The Burger Joint midway down the B pier.