CA prices are a little too intense for me. 

It's slow and labor intensive, but one thing I've done is use craigslist to monitor what things are renting for and how long they're on the market.You can use Evernote web clipper to save new listings (with pictures) in an area you're interested in, and add tags with the number of bedrooms and price range.

Is it very labor intensive?

Get used to that first, then manage it as a more intense investment.  

Vacation rentals are management intensive but the rental income is quite a bit higher.

But buying activity is so intense with value-add buyers always pumping capX dollars into older properties it makes me wonder if these properties will actually downgrade. 

Seems like you either have to put a ton of cash down to begin with (or pay all cash), or you need to add an intense amount of value to re-access the equity via a refinance...

If the Blackrocks of the world are buying 82k properties in a matter of five years or so, we all know they’re overpaying for these homes merely because they can and because they drive intense effieciencies in management.

I keep the workouts short but intense (think burpees, kettlebells, etc.) 

I could purchase a business or 2 that would make way more cashflow than most rental properties I've analyzed...and less upfront cash- and still be just as time intensive to start.