Virtually any purchase of RE in San Diego has produced outstanding return regardless of when it was purchased if it was held at least 10 years.  

If it is a good value add (is likely to produce a good value add) then maybe you should take it on as a value add (flip or buy n hold). 

However, my maintenance cost are somewhat offset on turnover of tenants as my duplex is still producing income on the turnover of a tenant, a SFH not so much.  

Selling the other mortgaged property would produce enough cash to fund the duplex's sale or renovation, net after capital gains for that property.Should I:1) Refi + reno and continue renting2) Refi + reno and sell3) Sell the duplex and the other leveraged property4) Sell the duplex and one of the lower cap rate, non-leveraged properties5) Something I'm not thinking of

In long run, 10-12 years, I want to have $500k+ in real estate producing 6-10% roi.

It is an amazing cash flowing property producing a solid $800 a month with more to be made as rents go up each time I get new tenants.

What are some of the no go areas in terms or crime rate or non cash flow producing properties?

My bottom line for me is to make sure that I buy a property that will produce positive cash flow and not require me to invest additional capital into the property post acquisition costs and related rehab.

I would use the 10 year performa to judge if the RE is likely to produce a good return.The result could very well be to sell (it likely is going to indicate to sell seeing that you apparently purchased without doing this exercise), but to decide to sell based on initial cash flow alone is making a decision without some critical information.good luck

My efforts to branch out into tertiary markets that seemed "undervalued"  (I went in for about a million of investment in upstate New York between 2003-2014) produced relatively little of value.