It sounds like a hard money lender is your best bet. 

I bet dollars to donuts this person is doing it.Also, a car is both a terrible and great way to judge someone's income and priorities.

The solution might even be in your next step, I have not used Quickbooks for real estate or business but I know that on your tax return each property has it's own column with its income and expenses detailed for the year and then they are all combined later into a single line item. 

There are some creative options I bet you could think of with family though.

I suggest to never bet on appreciation.

I bet he had people telling him that mobile homes were a bad idea, and that he was selling trailer trash. 

The bet is that the people will continue to rise every day and go to work, which we will, so long as we are poor enough.

I bet there's a hard money lender in your area who would look at it to give you short-term, bridge financing. 

There aren't really any formulas for this, your best bet might be to look at the pictures in rental comps other than that I would estimate the difference to be about $100 in rent for every $1000 of rental value if everything in a non-updated unit is clean, usable and looks reasonably nice.

You're best bet is to check meetup.com to see whats being scheduled.