I don't mean to bring discourse but I do want to mention one thing about riding illegal trails. I am not singling out what was previously mentioned here but speaking in general.
There are lots of ppl working hard to bring legal access for mountain bikers. For example, when Watchung legal access was denied, it was rather heart breaking. There were many on this board who attended meetings and fought hard for access. My personal opinion is that whether you get caught or not is not the issue. Like it or not, we are viewed as 1 group. Your actions may potentially affect the way we are viewed as a group entirely and it is my opinion that it can have an adverse effect on efforts made by others.
If you are interested...
https://www.mtbnj.com/forum/threads/watchung-reservation-mtb-access-this-is-it.42239/
Just my 2 cents and take it for whatever its worth.
Also, there are tons of awesome trails that you can ride legally. Is it really worth it to you that in the off chance you do get caught and can be fined up to $500?