For being such a large airport, the US Airways terminal at LGA is usually a breeze. With OLCI boarding passes in hand, I've parked (Lot 4) and been to the gate (particularly 11, 12, or shuttle) in 5 minutes.

Recently I've been doing a lot of flying through LNK. The rental car return right next to the terminal...you don't even cross the street! Again, with no bags to check and boarding passes in hand, I've parked the rental, dropped the keys in the return box, 1min walk inside then straight up the escalator. Done. All that's left is getting past the 7 bored TSA dorks manning the single security lane (which serves 2 whole gates.)