It is actually possible to employ a little trick which will let Pam reach the bus earlier, so you can get faster to the desert and start exploring the mines with a little more time! She will normally reach the bus at exactly 10.00am, but with this method she will reach it at 09.30am, so you get an extra 30min in-game time, which is roughly 20 extra seconds. So it's not a lot, but definitely helps you reach a level or two lower in the mines.
In order to get Pam to reach the bus faster, you need to run to her trailer before 08.30am. Stand right outside of the trailer so her patch will be blocked, and move away once she hits you. This will make her run towards the bus instead of walking, and she will be ready by 09.30 if done correctly. It might take a few tried before you consistently get the sweet spot, but it's worth getting used to do when you are going to the desert.