I had to learn to establish relationships with people in the real estate investment field prior to purchasing and building.

Appreciate the time and attention . 

Could seller finance (not recommended) to reduce initial burden and spread it out over time

I'm not bold enough to buy real estate at negative leverage - few deals in my area (and I presume, Manhattan), are trading at "Cap Rates" greater than 7%. 

By the time it gets there, the foundation is completely exposed. 

I’ve yet to see one that’s real.

I recently found these websites when looking through tax assessor's web page.

Note: I am under the impression that me material participating in this exercise will fall under the "Real Property Development or Redevelopment" activity, thereby allowing me to cost segregate the home construction cost.

How do I approach a potential buyer/real estate investor or as they refer to them "cash buyers"?

Quote from @Powell DiGangi: My guest policy is no more than ten days per month for any given person, which covers a boyfriend/girlfriend staying over on the weekends or a family member visiting. 30 days is a long time.