Good question, Bob. I'm nowhere near an FM DXer as I've been an AM man, so I'm assuming you mean reception under what's generally considered 'normal' reception conditions as opposed to the anomalies? It would be cool to find out that someone travelling north along U.S. 9 or U.S. 1 was getting WBEB near the Lincoln Tunnel on the average car radio. I know that a person can see the tower lights of Philly's Roxborough tower farm while in Bensalem (which is NE of the Philadelphia city limit). The ESB and the WTC had to've been visible southwest for a good distance into New Jerey as well. Such a situation would reduce that 85 mile separation considerably.
A buddy of mine had a Fisher receiver and a rotating roof antenna out on Long Island's north shore (Mount Sinai, Near Port Jefferson). Amazing setup. Even on non-tropo days he'd be able to spin the aerial and hear things like WODS from Boston, and WHOM from Mt. Washington .... all three of the 94.3 stations (New Haven, Huntington and Asbury Park) .... loads of goodies. I'm certain that someone even in the Five Boroughs who used a similar setup could beam in WBEB during normal reception conditions.
I once heard the then-WDVR 101.1 on a stock table radio from that JFK Airport area, but WCBS-FM was off the air at the time, hi. But there was one morning near the famed Massapequa Park when I was getting JB-105 out of Providence RI during a huge trope -- with WRFM on the air. If I'm not mistaken, all of Nassau County is within line-of-sight of the Empire State Building, off which WRFM broadcast.
The FM DXers aboard here would be able to tell you (and me

if the outdoor aerial system, plus the phase-lock circuitry, lobes in the desired station more than it nulls out the undesirable one ...... or if nulling out the closer station is the chief means by which to get something by default. As I said, my knowledge of FM reception and equipment is nowhere near that of AM.
The bet here is that it wouldn't be improbable to be able to see the top of the Empire State Building from the top of WBEB's antenna in Roxborough, hence vice-versa. The lines-of-sight at least should be very close. As such, along the hillier routes through New Jersey -- U.S. 206 and U.S. 22 along the Watchung Mountain -- normal conditions should be ripe to hear one station or the other.