I've worked with clients that have had to put more money up front into the transaction because the specific bank they wanted to work with required it.

I came across a website called Niche.com, and it tells you a little bit more about the demographics of an area, and one thing specifically it told me was about the percentage of people who rent/own in that zip code.

Diversity is usually the best in the STR industry so if one area is lacking you can always tap into the stronger property. 

We in the industry saw this after the Great Recession.

Quote from @Kathleen Dylan: You are in the most litigious, regulated corner of the world.

I am also toying with the idea of small industrial deals (with the help of someone who is in this space), but I personally do not have any experience in it. 

A few smaller private lenders may offer 2nd lien products, but they will be under very specific criteria and with a combined loan to value usually below 75%."

I've got wholesaling experience, and have worked in the mortgage industry as well.

Some lines of work are seasonal by nature - like snow removal jobs, entertainment industry, etc 

Get a local referral from someone who has actually used and closed with a specific HML.