You could refinance your house to extract the equity you've built and then rent it out to turn it into a long-term investment that continues to produce income. 

Hi, I am looking to buy very old house more than 100 years old but it produce good rental income , is the good rental income is worth taking the risk to buy a very old house , please help me to decide?

@Mayra Perez  being a real estate agent offers you unlimited earning potential, but it takes a lot of consistent action to implement systems that will produce consistent income.

You have reserves put aside which is excellent, the VA is no money down, and the income produced by the other 3 units will give you supplemental income while you establish yourself. 

My friend who always had a dog of that breed used a thick carpet that was padded, like one uses in a shower, when her dogs aged and lost bladder function and they produced enough urine to flood that.Can your flooring withstand this?

I put a small downpayment in and took a private loan (for the 25% ownership) from them that I'm paying back w/ interest and somehow we structured it to count as income for them produced by this same property...

In rent it produces 3,000 dollars a month. 

If we use $10K invested per property (20% of the lower of the OP price range) and a 10% S&P return (approximate lifetime rate of return of the S&P) would produce by $60K. 

The house is somewhat more likely to sell at auction now, since by auction time it will be a good-looking,  income-producing rental asset with stable tenants rather than an vermin-infested trash heap occupied by unstable addicts. 

Looking at LP+Promote level performance indicators might be an interesting exercise, but it doesn't produce much value to me because I'm not doing it to compare one investment option versus another, I'd be doing it just to see how high my IRR or multiple is.