Welcome Todd!! In regard to your question on whether a rupture from Tejon could
go all the way to the Cal/Mex border, there has been some dispute on this.
Since the San Andreas bends in this area some believe that this is impossible.
The bend requires the rupture to turn a corner. On the other hand, a series of
large earthquakes could gradually (over 10-100 years) relieve the stress
all the way down the fault.

The other camp says that a large rupture starting at Tejon could rupture the
fault sequentially in a great quake all the way to the border. Trenching
seems to show that great quakes occur nearly simultaneously in the area
however, dating is very poor on the trenching so this cannot be confirmed.
These occur on about a 500-year cycle (plus or minus a couple of hundred
years).

I tend to favor the first thought myself. There are no faults that have extended
ruptures around bends in one earthquake in the 1900's that I am aware of.
All the large ruptures occur on relatively straight fault segments, so I think
the prospect you describe is remote.