In my experience, the parking in the area is becoming a bit harder just after 9 p.m. IF you live East of Hamilton park and on weekends, again, IF you live East of Hamilton park since the mall shoppers park on the neighborhood streets to avoid paid parking in the Newport mall garage. That being said, you are still guaranteed a street spot but you may have to circle around a few times. Parking west of Hamilton Park remains very easy.
If you live East of Hamilton park, a walk to Newport PATH is an easy 8-9 min. Grove st PATH is also within an 8-9 min walk. West of the park, add a couple of minutes to your walk.
The only time the street parking does become challenging is after a snow storm as many spots are taken by the snow. Luckily, they suspend street cleaning for a few days until the snow has melted and you don't have to worry about moving your car.
Lastly, residents of Hamilton Park area are entitled to a special discount parking rate in the Newport mall garage , which is only 2-5 min walk from the area depending on where in HP area you are. Last time I checked (2 years ago) that rate was $85/mo with proof of residency in the area. it may be a bit higher now.
All in all, we are enjoying the best of two worlds in Hamilton park - an easy walk to the PATH, clean reliable trains to Manhattan 24/7 (7 min train ride to downtown and 15 to min midtown) and an option of having a car and being able to park on the same block most of the time.