First you'll need 20% of the ARV to put down and then you'll need to reach out to private money lenders for the rest.

what is lot rent, what is the utilities....private or city water/sewer. 

How does someone in my position with the experience of finding the best deals, knowing multiple contractors for repairs, and the capacity to put it all together, find private lenders to fund deals?

Working with a private bank to see about 10% down with interest only until the property is built.

When investing with private money.

Rather than spend time looking for note investors, I'd recommend you look for private lenders or a bank that can provide you with funds at closing.

Looking to get into using private or self directed IRA.

Background is international accounting in the private sector.

Could I use private money to cover those costs?

Best bet is to keep your current rental (assuming your happy with it) and buy another property to live in - whether SFR or MFR is up to You & Wife.