NJ DeCavalcante's operations are run by the rest of the NYC families. What's there to be taken is all Albanian.
I'm sure they have a few things involving gambling, loansharking, construction and a small bit of extortion. But you're right, the Five Families control a good majority of the operations in Jersey, some of which the DeCavalcante's are somewhat involved. But they are small potatoes compared to NYC now
"Don't ever go against the family again. Ever"- Michael Corleone