You'll need the separate bank accounts, debit/credit cards, extra accounting/bookkeeping, all the attorney fees to setup and manage these enttiies, can't share the umbrella policy..Yes, people talk about the Due on Sale clause, but just about everybody says it never gets called unless you stop making your payments. 

Is this recommended, or should I just get an umbrella policy?

However, I usually advise just to get a really good (and large) umbrella insurance policy on the property instead.

Should I start an LLC or umbrella insurance is enough6.

Simple works for me - 21 SFHs, 1 checking account, 1 spreadsheet, 1 LLC, 1 umbrella policy, 1 Ford Ranger, 1 cell phone, 1 Cozy account.

Have good coverages on your landlord insurance policies and get a minimum $1mil umbrella policy  

Insurance would cover it, I would pay the deductible, and no assets would be lost.If you are in an area like San Diego where people are more likely to sue, a judge is more likely to find you guilty, and the payout is likely to be higher, then you may consider an umbrella insurance policy.

The DSCR may be a fit, there also may be other options under the portfolio umbrella, sometimes you can get exceptions to the rule if it makes sense.

You can also insulate yourself with umbrella insurance.

I also believe that La Jolla is considered a "Special Community" but still under the umbrella of the "City of San Diego".