Being a longtime fan of the Greenwood Lake Division, here are a couple things I can offer:
1) Yes, the ROW was buried under I-287 just south of Union Ave.
2) The bike path, long under consideration but not yet started, is designed so that it would not interfere with any rail operations, including restoration of passenger service.
3) The Wanaque station was demolished in late 1966, I believe, after a fire not long after passenger service ended.
4) The rails have been lifted in spots though Pequannock, but in the long run, that would not be a deal-breaker if restoration of passenger service is considered as the ROW and tracks would be rebuilt anyway. (Unlike reopening freight line, where slow speeds can be tolerated.)
5) The trestle over the Pompton River is in very bad shape. It has been damaged by several fires on the wooden track and a derailment or two that came in contract with the structure. Plates were welded to the ends of the trestle to prevent anyone crossing it.
6) Routing passenger service from the NYS&W tracks west of Pompton Junction down the Greenwood Lake -- which would be a much shorter commute for passengers upper Passaic and Sussex counties -- would require the restoration of the southwest connection between the GL and NYS&W, which crossed over the Pompton River. It was removed in the late 1950s, and the embankment can still be seen leading off the Greenwood Lake opposite Ber Plastics. However, the embankment on the NYS&W side was removed in the late 1980s for the mitigation pond for the construction of I-287. That would be a formidable environmental barrier to overcome.
7) For a few years Mountain View functioned similar to the Montclair University station. When passenger trains on the DL&W Boonton Line were diverted onto the Greenwood Lake beginning in 1963 (when the Boonton Line around Garrett Mountain was abandoned for the construction of I-80), the single-track Erie Mountain View station reconfigured so that the new wye to the Boonton Line split off from the GL east of the station, so that two tracks ran through the station: One to the GL to Wanaque and the other the Boonton Line west to Dover. This arrangement allowed for off-peak shuttle trains to be waiting to take GL passengers to Wanaque who transfered from Boonton Line trains across the platform. I would have to check my old timetables, but I think by the time service to Wanaque was abandoned in 1966, all the trains to that destination were shuttles, with no direct service between Wanaque and Hoboken.
8) In the late 80s and early 90s Passaic County and the state were considering building a road on the ROW west of the site of the Wanaque station from Ringwood Ave. near West Brook Road, reconnecting with Ringwood Ave. several miles south to alleviate traffic on Ringwood Ave. It was determined it would not make a big difference and in fact would create bottlenecks were the bypass connected with Ringwood Ave.
9) Pompton-Riverdale station still had an agent until the summer of 1970, four years after passenger serviced ended. Apparently there was still enough local freight business to justify the agent until he retired.
10) The Pompton Plains station was recently restored.
"But Dad. It's Smokey!"
However, we could make an L-shaped platform on one part of the station, with parking. The northern half of the L is the Wanaque Extension platform, the southern end of the platform is the Susquehanna Line platform. Makes it cheaper than 3 platforms with high-level, basically one doing both lines.
