I think in overheated markets like Cali you are dealing with mini bubbles.

Can you create a mini-suite?

The cheapest, most efficient and versatile is a mini van with all the rear seats out.  

BRRRR is not a great strategy in most markets now because inventory to buy is low so you have to pay more which shrinks your mini-renovation to rent ratio due to rates as well.LLCs are of no use to you now at all unless you are going to run a business through it before investing in real estate for two years.

Then you could have one of those Ductless Mini Split systems installed in the 2nd unit.

Windows get the cheapo $5 mini blinds which I change out between vacancies.I usually paint whole unit same color like Linen or Dover white.

It works in the South, except for Austin TX now which has become mini California.....yuck!  

I figured the investment of making this a normal function kitchen was more important than going cheap like the competition on a portal stove top, and mini fridge.

My wife and I have a goal of doing a mini retirement somewhere in the next 5 years. 

I bought mine during a flash 40% off sale. the format makes it easy to learn with plenty of mini questions throughout the lessons, and the lessons themselves are each short, but informative.