I did RE (LTR singles and multis) because it's what I knew. 

For example the city of Frisco is a pretty popular place to live today, population over 200,000, and I'll bet there are less than 100 duplexes.   

@Josh Caldwell  its the only state in the Union I have not personally set foot in or on.I bet its a sleeper don't hear anything about it really.... good luck with it.

I have a few single family homes in the area and have had several multi families in the past.

If your budget will allow for a purchase of $400k or more, a single-family house within walking distance of the beach will likely yield higher return and a larger runway for appreciation.  4-bedroom channel homes in the popular Cherry Grove section of North Myrtle Beach go for around $600-$800k. 

Spring is one of the main times folks do it so get on it now and I bet you find some good stuff.

Every city has many, many markets - there is no single market for a city like that. 

What are neighborhoods to stay away from and what are the best places to invest in rental single family homes?

I have a unique situation where a long time family friend inherited a single family house in Jersey City from her deceased mother.  

Your best bet will be to work the process a slow as it is.