Your results will be better, albeit more work.You could also create a holdings company for all your entities as I have done with various digital enterprises.

I was in love with micro lending until the account hit 5 digits and I started to get nervous, so I opened a Prosper account to build that and when that hit 5 figures I started saving for my first rental. 

This attracts a lot of out of state investors who think that the low barrier to entry and high tenant pool equates to high cash flow at double digit rates as it would appear on paper. 

Don't tell anyone that I told you, but...just wait until the Casinos are approved in the 6 sites scheduled for development.

I own a digital marketing agency (high stress for sure), make 7+ figures, and have a family of four to support (my wife doesn't work).

. $4500 seems like A LOT of money to transfer our digital plans into CAD (the contractor already built-out our design ideas on his laptop's software) and have an engineer ensure we're using the right beams in the right places.

Unless you can provide your private lender with secured double digit returns, I agree with most, your dad may have to do this on his own, or simply have you intern with him on this deal. 

And I would argue, likely lower expenses and less headaches.I think the best bet would be pulling a Donald Trump and getting in on an entertainment / casino / development deal.

Personally I would invest in a fund with an 8%+ preferred return with equity split that pushes the realized return to double digits before I would pay off that debt.

I know of a few funds that offer preferred returns, and project double digit returns in total.