In the past year, I've probably done about 40 runs from CLT-SAN on US. Even though I've never had to make the trek over to T1 from T2 to catch a flight, I would second the advice from one poster who suggests just walking it. You will most likely park at Gate 33 or 34. If so, this will put you right at the escalator down to baggage claim and the terminal exit. Out the door, you can hang a left and just make a quick walk down to T1.
I believe it will take you longer to catch the bus, circle out of T2, stop at a few traffic lights, wrestle past other folks making their way between terminals, trip over a couple strollers, etc. I've often jumped off the Hertz shuttle at T1 and walked to T2 just because I can get there faster that way.
Good luck!
Jammer