I live in JC and commuted to Chelsea (15th & 9th) for 3 years - it’s really easy as long as you’re near the 33rd street PATH line. However I wouldn’t bet on it only taking you 30 mins due to a number of variables. I’m ~10 min walk from Grove Street and would always budget at least 45 mins to be safe. But it’s a straight shot and only requires you to take 1 mode of transportation.