The answer normally lies in what your goals are.  

Do you have an LLC set up?

And just set up separate bank accounts for the separate properties?

We set a minimum stay length of 30 days, when people search for stays of 30 days or longer it filters out most of the STR rentals and those who focus on the mid-term space rise to the top.2.

We do work all over Northern California.I'm not the expert in this area, but I believe it's the case that financing against future receivables would set up some unacceptable risks for company valuation. 

I am a realtor here in Houston, working with investors with a variety of investment goals.

Other than that it's all goal dependent, do you want cash flow, stack big checks, and create tax savings?

Whats your goal when investing? 

@Chris Billington there are a few options if your looking to buy "prehabbed" with a goal to refi and cash out.

I have a similar set up in Colorado Springs - it depends on your insurance company.