Triker,
To operate on the MEC out of service track in Maine, you need to get a permit from the DOT. In NH, the state allows you to run on The Wolfeboro line as far East as RT16, and The Conway Branch track in Center Ossippee From RT28 to RT16. I joined the CVRTC to give them my support, and I suggest that anyone with a rail vehicle of any kind that wants to run there do the same. This also gives you insurance. In CT, I am a member of the FVRR (A volunteer group for the Essex Valley RR). I use my car, when we do track work on the VRR out of service track. In NY, I volunteer for the UHRR to pick up trash along the ROW, and they have allowed me access. I am in the process of obtaining a permit from York County Parks, PA to ride the out of service track down there this summer.
As you can see, you cant just go an ride on a track. It's really worth the effort, to do it the right way!
Hank