Start to narrow down what specifically you are looking for and then start building relationships with those that will help you to meet those goals (real estate agents and lenders). 

We only have about 3-4 months of emergency savings at this timeOptions we are evaluating: Continue as-is and use the HELOC to fund our primary residence improvements and any emergencies we haveSell Rental B and collect about 700-800k in cash after taxes/fees.

Most gurus focus on one narrow concept (e.g.

Like if I were to look at the contiguous US as a whole, how would you narrow down your location in which to invest?

They seem pretty excellent, but I am like you, I have a plan "B", and plan "C" just in case...Trust, but VERIFY!

Also what neighborhoods would be considered B and C neighborhood in Pittsburgh?

Jacksonville is the biggest city (landwise) on continental U.S. and is growing rapidly so I would suggest doing your research of the different parts of the city and narrowing from there.

I don't invest in NJ, but I would think you would need to narrow down your area scope a bit.  

I would start by narrowing the geography that you would like to purchase a property. 

If you're buying a commercial property (5+ units or pure commercial) then your options are narrower.