Chris,
Regarding the San Andreas and hot springs, I have a story that might interest you. In August of 1998, several of us hiked to Waterman Canyon around San Bernadino, CA, to see Waterman Geyser. Someone had a topo map and we checked it to find that the geyser was only a mile or two from the San Andreas & not far from I-15.
Anyway, I'm not sure what I expected, but I did not expect massive weeds, a creek, and terrain that fell and rose abruptly within short distances. There was little around there at the time except for a church retreat, and the geyser itself was a bit underwhelming. That is, until we used the compost thermometer that I brought to measure the water coming from the geyser. We measured it several times and it averaged 123 degrees F. - warmer than a hot tub anyway!
Shortly afterward, I heard that the area near the geyser was being developed. Between development, fires and the quakes since then, I have no idea what became of that geyser. All I know is that on that afternoon in August of 1998, it was certainly a hot spring.
Beth