I had purchased a building in 2009 in the Old West End and I was standing outside when a man approached me saying he owned a 45 unit apartment building with a 30 car parking garage across the street that he wanted to sell to me.

If they had a verbal agreement with the last tenant,   and the last tenant gave notice or has officially abandoned per definition thereof  (you can look for things like them having cancelled their utility accounts, emptied unit of their belongings, etc)  then they can't prove anything and maybe you can use that approach.   

I'm noob and just building my own goals so helpful to see other approaches.

Sounds like you are approaching "Hurt City".

I completely agree with the business hours approach to repairs.

If you do find something approaching the 1% rule, it very likely could be a D-class neighborhood.

However, these investors have experience and knowledge in their market and most importantly are NOT using the "no money" approach because they can't afford to put down  money for a traditional down payment.

That would leave us with around $70k liquid cash.We rent an apartment month-to-month until we find a good duplex to purchase (ideally within 1 year).We house-hack the duplex until we accumulate enough cash to buy a SFH for ourselves (3-5 years).We retain ownership of the duplex and rent out both units.In my mind, this approach could "get the ball rolling", considering we can't afford to buy an investment property with our current circumstances, nor would we be able to for many years.What would you do if you were in the same boat?

Getting a Collection Guarantee When you’re underwriting a deal and you approach it conservatively, you take into consideration that rent collections may drop in the next 6 to 12 months.

@Joe Jor great points on the buy-and-hold approach.