The last known grizzly killed in California was in 1925 in Trabuco Canyon, southeast of Santa Ana. It was an old sow. There have been reported sightings since in the Sierras, but no confirmations.
Larry, if you really wanted to go on a "Bigfoot Expedition", I suspect the best location would be in the coastal British Columbia area. The vast majority of sightings have been in BC, and there are still VAST remote, roadless areas there.
In 1974 I was driving to Alaska from the states and stopped at a roadhouse near Williams, BC. There was a giant, furry statue of a Sasquatch in front of the place. I asked the lady inside if there had been any recent sightings in the area. She told me that there were always sightings in an Indian village "nearby" called Bella Coola. She gave me basic directions, so off I went.
Of course, it was not "nearby". It was over 100 miles down a bumpy dirt road to the coast. At that time it was a VERY lonely place. Once there I asked the folks I saw about Sasquatch, and they all said sure, they were around. One old fellow told me that some teens saw one just a few days before.
Most of the "Bigfoot Expeditions" one hears about are always in the U.S. Northwest. Since most sightings are in BC, I would think that would be a better place to try. I wonder what baiting (like for bear) and calling might accomplish in a place like Bella Coola.
One problem with Canada is that you won't be allowed to carry a firearm. One would have to rely on a good tree stand (attached WAY UP the tree, in case those things are as tall as reported).