@Michelle German I think you're both thinking about the right things. Markets oscillate, and being willing to take some risks is how people are able to capitalize on opportunities like this. But on the brink of retirement, "excessive" risk is not the right move either. With that said, I think there are a couple of things you might want to add into your discussion to help you make the decision:
First, how long until you want to retire? If it's 10 years from now, you'll have plenty of time to get back into the Southern California market if that's what you decide. The chances of prices continuing on this trend for the next 10 years are pretty slim (in my opinion) and you will be able to watch the market and pick your time to get back in. Additionally, you won't be trying to "break into" the SoCal market as many other people trying to move here, you'll have $500k in your hands to get you in the door.
Secondly, if you are wanting to collect rents passively while you travel the world (Good for you!), ask yourselves if you need those rents to come from California. Given an extra $500k to put in rental property somewhere, I'm not sure Southern California would be my first choice personally. If I was going to be jetting around the globe anyway and not local, I'd probably look at more "landlord friendly" states with better ROI. That could turn into 10-20 units in other markets with a much better rent return, depending on the timing.
Just some additional things you might want to consider. With all that said, if you do decide to look at selling, @Tyler Hungerford is a great resource to talk to. I'm happy to help any way I can as well.
Good luck to you!