42k Cash: Flip, SF Rent, or Duplex Rent?

[William Huston]

I currently have 42k in cash with another 50k tied up in lendingclub slowing being payed out to me. I currently own a handful of rentals all over the country from being in the military. I never bought the houses with the intentions of maxing profits once they became a rental, so my ROI is pretty low right now on them.

I would love to do a Fix and Flip, but from the reading i have been doing it seems i need slightly more cash on hand to properly do one yet. I have thought about buying another house if the numbers showed good 15%+ CoC, but the last week i went to a investment meetup group locally and one of the guys who claims to have about 40 rentals, said i should invest in a 4plex, but i know very little about them and what to look for on searching for one to make sure its a good investment. It seems nearly all of the 4plex's i see for sale are in the rough "ghetto" parts of town near me.

If you were in my shoes, what would you do and why?