Several years ago I lived in Morris County and I know the trains and roads a little bit. It looks like your major options are Stanhope, which might not offer many more trains than Hackettstown but is the closest other station, Dover at 16.6 miles or so up Rte 46 or Gladstone-Peapack at 15.8 miles or so up Schooley's Mountain road and over to 206. I know Dover and Gladstone Peapack used to offer very early train service so it's a pick your poison kind of thing. I think a bike locked in Peapack would be better off than one in Dover, if that's what you plan to do with it. Does NJ Transit have any sort of Bike Locker facilities?