You don't necessarily have to get your Toyota 4Runner smog checked in the
county it is registered in, you only have to ensure the county you want to
get a smog inspection in is of the same "smog check area" type as the one
it's registered in currently. The three smog check area types are... Basic,
Enhanced, and Change of Ownership.
Southern California, for the most part, is an Enhanced Smog Check Area. Smog
check stations in Enhanced smog check areas of the state can inspect and
certify your Toyota 4Runner for the purposes of title transfer; such as in
this case. If your Toyota is registered in an Enhanced smog check area, a
Basic area smog center would not be able to certify your 4Runner. Sounds
like you are at an advantage in this case; coming down from a Basic area to
an Enhanced area.
Simply drive your 1996 Toyota 4Runner to a local smog test center and
explain you need a smog check because you are planning on selling your
4Runner. They will enter this information into the smog machine and should
perform the smog test without any problem.