If you're looking for the cheapest route, conventional may be a better bet.

This is true for all private money lending situations..

Quote from @Scott Tennell: For real estate investors who have worked with private money lenders, what strategies have you found most effective in structuring deals to ensure both parties are protected and the funding process runs smoothly? 

This is a 'nicer' mobile home, double wide, 1998, shaped / looks more like a 'house', attached garage, on a very beautiful private lot. 

Just sent you a private message, let's get together soon

@Ji Yang, I advise reading articles by @Ian Ippolito (also in BiggerPockets) online (google him) about how to vet sponsers and what to look at in a private placement memorandum.

I bet that you can pay off this debt in 1 year or much less.

We used $100k of private money and the rest was personal cash.

Several options you can explore to get the down payment capital: Solo401k; HELOC on personal residence or from equity of the SFR; Cash Value Life Insurance Policy; Business Credit; Private Lenders, to name a few.

When you have a duplex and tenants on both sides stay for ten years, it almost guarantees that something isn't right.I would study your market and determine the value of your rental, because I bet you are losing money every month.