I assume that you are focused on arriving to Port Authority ("PA") at 42nd and 8th ave, because you need to arrive to "Midtown" area of Manhattan.
The #32 DeCamp bus stops at the corner of Union and Park Avenue, 0.4 miles from 11 Elmwood Ave, Belleville, NJ (the page I saw your question on). Or, if you walk or drive about 1 mile over to Clifton Commons, a shopping center in Nutley, NJ, which has free commuter "park and ride" spaces, there is (1) NJ Transit bus #192 or 195 (check the NJ Transit site) that runs on Kingsland Avenue and goes into PA, and there is (2) a NJ Transit bus that runs on Route 3 (behind Clifton Commons), that is an express bus into PA.
You can also drive to Newark Penn Station (about 15 minutes from Belleville, depending on traffic), get a monthly Edison parking pass for $199 (there is one right behind Penn Station Newark that is super safe), and either take the NJ transit PATH train to World trade center ($80 monthly unlimited pass), switching at Journal Square, I believe (by walking across the platform) to go uptown and arrive at 33rd street (PA is at 38th street) - OR you can also get a slew of regular trains that stop at Newark Penn Station, then Secaucus, but then go on to NY Penn Station (which is at 34th and 8th ave). They also have a monthly pass option.
Of course, you can also stay on the PATH to world trade center, then go outside, walk a couple blocks, and get on the subway system (c,e,2,3, or 4/5).
Blocks in Manhattan are short running N-S, so there isn't much distance between NY Penn and PA.
I agree that NJ Transit has better reliability than DeCamp; it also has more busses running in and out of NY - morning, about every 15-30 minutes depending on the line. That's particularly helpful when oyu get out at different times each day.
I've done all of these, currently use PATH because my company relocated to Church Street and is literally 1 block from world trade center.