I've heard of rate cap locks going from $40k to over $1M in some instances.  

If i can invest it and make a significant better return after tax than paying it down I would do that but in this instance you will never be able to achieve returns that match credit card debt.

There are plenty of places in CA I would never live or do I like.. for instance Barstow would not be on the top of my list :)  

And a business license is nothing and not required in almost all instances other than where you might be domiciled.  

For instance, unless specifically called for in the Articles or Organization, LLCs are not required to have Boards of Directors, Officers, annual meetings, bylaws, resolutions etc.

The Aura frame package, for instance, came in at just $5,000.

Alternatively they can purchase a portfolio of occupied homes at a discounted price because the seller of the portfolio in most instances first tried their hand at selling the homes individually to the owner occupant and after experiencing 13-15% in disposition fees and expenses realized its not worth the effort and better to package the assets and sell discounted to another investor.Keep in mind, most of these SFH's are in stagnant markets meaning limited appreciation and if you ever took the time to look at an amortization schedule  there's no meaningful principal paydown for many years.

not sure what your comparing it to though.but take Tyler for instance.. he plunked down some amount of cash I would suspect and pure guess in the 40k range for this property.. he could alternatively gone to Richmond CA and bought small bungalow or duplex for 200 to 225k and put 40k down and would cash flow neutral.. but his tenant would be paying down his mortgage note... 

For instance, there is currently a nursing shortage across the US, and traveling nurses help to alleviate it.

In all of those instances the activity of the property will still be reported on your joint tax return.