The macro view seems like people are leaving town, but it's mainly the boomer and older generation looking to retire and avoid snowy winters. 

Macro big picture plus Decisiveness is the key.

January and February are now getting interest from retired people and snowbirds that want to visit in the less busy/noisy times.  

You can even learn to use macros in excel to make life easier as well.

Get micro instead of macro.  

A positive macro-trend is in place.

The answer to this question is tough, as its not really specific but here's a macro answer (assuming your buying 2-4 units):-Budget/level of rehab: The amount you have to spend and the amount of work you're willing to do will effect the answer, but if your budget is sub $300k you'll have more luck in central or Southern Jersey .In Northern NJ a budget of $300k MIGHT get you a 2 family that needs work (in D class neighborhoods $300k will go a lot further) look at East Orange, Newark, Hillside, Orange and Irvington-Form of tender: Are you paying with cash?

Unless you mean on a macro level where more buyers tend to increase asset inflation.

He is noisy and obnoxious and leaves trash in the common areas.

How I personally would start is on the macro level, and from there do a bit of leg work and start analyzing specific areas within the city that you want to invest in.