I don't know what you could do other than giving verbal / written expressions of how you are unpleased with the way they keep the place.

California and neighboring States were "infamous" since that was a driver in their bankrupcy during the prior 2007/2008 crash. 

Unless the market crashes during your rehab, that also really shouldn't affect your investment strategy.

This can happen, and one older gentleman at my local REIA recently told the story of losing a 44 million dollar portfolio during the last crash. 

Appraisers were more cautious then due to the crash, and it was harder to access equity.

Riding the appreciation wave is fun and can last a long-time, but the wave will crash ashore at some point.  

While you can make money and I have supported my family this way, I also have seen may, may crash and burn.

The US had a crash in 2007/2008, but house prices bounced back. 

If you are paying rent right now, you are just throwing away money waiting for the perfect time (market crash, which may not happen anytime soon).

For instance, during the 2008 financial crash, the majority of multi-family units in Las Vegas were vacant.In 15+ years of dealing with residential and commercial investments, I have never seen any investor sell a performing asset. 100% of the time, the property was losing money either through tenant issues or deferred maintenance.While there are some multifamily where the interiors have been updated, very few have had the expensive infrastructure replaced.