I do not have my numbers as well organized as @Greg Scott but my estimate is upper 20% annual return on average.The 3 i am currently invested in, one seems likely to produce an outstanding return (High risk, high reward), one is conservative and is performing to projections, and one i have significant concerns about but has not had a capital call.  

Consider selling the duplex to put it into a higher income producing asset (out of state, DST, something).

@Mark Allen Hopefully, this gold mine is still producing.

Do you have any other income producing assets? 

Looks like a young group of professionals with not enough experience, navigating through various market cycles to produce an accurate  business case.  

Do you have a web presence?

I'm curious how something like that would work with land that doesn't have an income producing rental on it yet? 

@Nathan Gesner  Don't believe everything you read, especially on the web. 

They do an inspection, look for potential costs with repairs and produce a final report.

If the real estate is producing a steady return, you can make more aggressive bets with stocks or other alt assets.