Here in the crowded Northeast of NJ/NY/E.PA, it is difficult to find some quality spots.
With 2 little girls at home, I have a difficult time getting away for some "me time". And when I do, I often try and go early, so I don't miss much of the day. Also, things can tend to get a little crowded here - especially at places just off the interstates. I've managed to find some great spots at my local state park (though I now need to share it with MTBers), local game lands, some other state parks within 75min drive, and even some county and "private" open space places too.
Because of my infrequent venturing, and short window to do so, I am increasingly keeping these places close to my chest. I used to be a hike leader for the AMC, but have since shied away from that, and rather than sharing my places, I have tried to keep them secret. Additionally - and since I am such an introvert - I tend to enjoy the woods either alone or in a tiny group of close friends. I tend to not like the 'social' nature of the group-led AMC hikes. Also, I like to do my outings at my pace ("fast") and start time ("early"), and would rather not want to cater to the needs of a larger group (late start, slow pace, all-day adventure).
EDIT: I'd like to add that on a recent outing to my local Nat.Rec. Area, I was able to find some trails to give me the mileage and solitude that I desired. I didn't see another person until the return end of my loop (along popular trails). Bliss.
Lastly, I want to try and keep my favorite places to myself, and then share them (and the reasons why I like them) with my girls when the time comes. Sharing the places with too many other people might sully the "specialness" that sharing the secret place with my girls would bring.