I am looking at the NJ building code and trying to find the section about how high off the ground a porch can be without needing a railing. Any ideas?
I don't know that, but do know that when we were in our first house, our realtor told us not to remove railings on a 3-step stairs in the front yard. Because FHA mortgages required it. So as long as you are checking, might want to double check to see if FHA is more stringent than local code.
See Section R312.1., which requires guards if the porch is more than 30 inches above the adjacent grade.
Here is a link that might be useful: NJ Residential Building Code