It's not great news. New Jersey is restrictive when it comes to restoring gun rights.
Your right to vote in New Jersey was automatically restored to you after the completion of your probation. For the restoration of all other NJ rights, especially your firearms rights, you will need a pardon from the governor. [N.J. Stat. Ann. 5 2A:167-5]
Pardons are extremely rare. But they don't cost anything to apply and there's no reason not to go for one. The forms for the pardon are not on line. You can read more about the pardon here
You could likely get the forms from the court where your conviction took place or directly from the NJ Parole Board, since they do the screening for the governor.
Once your gun rights are restored in New Jersey, then usually the Federal government will go along with it, and you could possess a weapon lawfully in Pennsylvania.
I have checked to see whether you could meanwhile use a black powder gun in PA. The Federal government exempts certain antique guns and replicas from firearms prohibitions and a felon could possess one if the state allows it. Unfortunately, Pennsylvania considers antique guns firearms too, so that doesn't help you.
Your only avenue would be the gubernatorial pardon.