I lived on Sherman Avenue in the Heights for 3 years and Bowers & Central Avenue isn't that bad.
The border line is Paterson Plank & Palisades Avenue with is the border line for Union City & JCH.
I really would avoid Palisades Ave. I only used it to catch the #123 to NY in the a.m and in the evening. It gets very quiet and desolate at night.
Parking, you will have to get a permit from the JC Parking Authority which is next to the post office on Central Ave.
Central Avenue isn't that bad, it has its moments like any quite street in NY but basically is cool.
The Shop & Stop there is ok, but I would suggest going to Shop Rite, where there is one located at the bottom of the Congress St. LIght Rail and one is near the Newport Mall.
Like I said the NJ Transit bus #123 runs on Palisades Ave, and goes straight into NY. It' cost like 4.80 one way and the monthly pass would be a zone three pass and cost $136.00/month.
There is a new bus I heard that runs on Central and is operated by NJ Transit. When I lived there the Coach 10 & 99 ran but I heard they no longer do.
Basically my three years in JCH was ok. I had no problems and it's an up and coming area.
I left because I got homesick and moved back to NY because everything closed to dang early, lol.
Hope this helps you.