It can get harder if its owned by a corporation, but many are owned just by the individual.

For example, if a major corporation is opening a factory within the next year, that will create 1,000 jobs over a 3 year period, is that a good incentive to potentially invest in that city?

At the corporate level, most places are not hiring. 

The alternative is to work until I am 50 or 55 and invest that $100k passive income into other investment avenues to setup even further success while still making good money in corporate America.Those were pretty long winded examples to basically get across my question of do you have any good methods for how many of these methods/strategies break the boundary of straight investing to actually becoming primary income for the investor.

Not much of a deal but after a few thousand dollars of paint and flooring, I have a corporate tenant on a three year lease paying $350 over my PITI.

You will typically need to provide ID, application (they will provide this), corporate documents if going into LLC name instead of individual, 2 months bank statements showing available funds for down payment, fees, points, as well as typically 3-6 months reserves to ensure you are able to make the interest only payments while fixing up the property and before it sells.Any other questions or if you would like more detail feel free to ask.

However, it only protects you from one type of liability: accidents.After that you want to compartmentalize your assets, which is often accomplished through the use of LLCs or corporations.

I was looking into doing corporate rentals.

And the correction will be triggered by outside forces affecting real estate (corporate debt, student loan debt, international policies that affect outside investors, trade wars, etc).  

I’ve dealt with both short term rentals and hotels (franchise, corporate, leased, owned) The challenge is that you have no control of the building.