However, it took work to build that relationship and create a mutual set of expectations before it became passive.Everyone needs mailbox money.

You must always have a great and strong relationship with your Hard Money Investors and with your Private Investors!

Or are you more interested in (and willing to) engage in more of a slower, relationship-oriented approach to negotiating? 

Now I can just pick up the phone as I have built out many solid relationships with very knowledgeable investors.

I'm building relationships right now and don't want to make any silly mistakes.

It would depend on your banking relationship. 

By doing this, you've created a relationship by trying to provide value.

I understand that they can be dangerous from the perspective of historically they were predatory and people purchased properties that they couldn't afford, getting hit hard with the intro interest-only period of 5/7/10 years expire... but I see it as a flexibility option.

You have to approach as if you were just looking for homes in the area and develop a relationship.

So I thought it was a great opportunity as we demo the casita (keeping the original brick exterior for the historic neighborhood) to expand it into a duplex.