Trouble Comparing Rent

[Phil Spadaro]

I am a new investor ready to put in a cash offer on a property in new jersey with the intent to BRRRR. Short sell opportunity that looks promising from a purchase price/rehab cost/ ARV perspective. Where I am running into issues is comping rent in the area. I am having a terribly hard time finding hardly anything for rent in the immediate area. Is this a good problem? (Low supply) or red flag ( low supply because no demand)

I checked 

Craigslist

FB Marketplace

Zillow

Trulia

Rent.com

Are there any other places I should be checking. My Realtor seems to be having trouble finding comparable rents as well.

Any advice?