Anthony Gray,
I don't know if you mean underrated in the context of the ratings with the magazines or under the radar.
There seems to be a good number of courses that are virtually unknown outside of their particular locale.
Besides the known clubs toward Northern NJ like
Ridgewood
Baltusrol Upper
Baltusrol Lower
Plainfield
Somerset Hills
There are
Essex County
The Knoll
Mt Ridge
Hackensack
Forsgate
Hollywood.
Montclair
Alpine
Canoe Brook
Just to name a few.
In addition to these courses there are a good number of sporty, fun courses to play, such as
Preakness Hills
Bedens Brook
Bowling Green
Deal
Echo Lake
Essex Fells
Rock Spring
Fairmont
Morris County
Glen Ridge
Knickerbocker
Lake Mohawk
Manasquan River
Rockaway River
Rumson
Shackamaxon
Spring Lake
Springdale
Suburban
Upper Montclair
And others which I've forgotten or haven't played.