I think the best course for me would be to buy some 20+ year old Californian wines through a private source to see if it’s for me. I have enjoyed wines from a lot of different regions, but it’s very seldom I open a bottle that’s not Bordeaux at home for myself. When there’s a party to appeal to a wider audience I generally have organized for red a crowd pleaser Californian Cab like a silver oak, a Barolo for a lighter red, and then two Chardonnay - a Californian and then an un-oaked Chablis. Or a variation of this and everyone is happy.