I am looking out of state for a better monthly ROI to help supplement my own mortgage/passive income. 

Thereafter I’m trying to consider other ways to create sustainable cash flow/income that can supplement the cash flow fluctuations of short-term rentals.

So to confirm my understanding then, the Supplemental Tax bill is basically just the difference between the assessed value of the prior owner and my new assessed value (ie my purchase price) * the tax rate I looked up on the auditor's website * a pro-rating based on when I bought the property during the year, right?

I’m not going to get rich off that, but it’ll help supplement my 401k retirement income.

If that's the only cash for your BRRRR you would likely need hard money to supplement the down payment, the closing costs, and the rehab. 

It's a great supplement to retirement, or it could just be your retirement plan.

Taxpayers do not want to supplement investors with low down payments on property loans nor take on the risk of an investment property loan that originated less than a year ago as an o/o...again, no equity.

Here in my neck of California the re-assessment occurs as of the date of sale so that we get supplemental tax bills in year 1 rather than in year 2.   

But I am seeking cashflow to supplement a paycheck.

My original goal of the handyman business was to supplement my REI projects