The opening scene is said to take place in Dime Box, Texas which is surrounded by mountains as one would see in the western parts of the state. The real Dime Box a small, unincorporated town with a few hundred residents, no where close to the decent sized city portrayed in the episode. It is located in south-central Texas which is subtropical, not arid as it appears on the show.
Around 7min, Cahill responds to Trivette's question that Walker stood her up on her birthday. Unless this was for some other time, just 2 episodes prior (Codename: Dragonfly), she was given a surprise celebration by Trivette, Walker, and Parker--even when she said she didn't want to celebrate.