I expect that limiting access to Success may be the start of a typical Dillon campaign to market the property. The TPL has an option to buy the land once Dillon finishes cutting it. By actually limiting the access or implying that it may be limited, the area gets in the news, various articles are published decrying that access to an area is going to be lost. Then the TPL comes out with a fund raising campaign to "save" access to the area, this drives the property to the top of conservation funding lists and eventually a deal is brokered. Then prsss releases are issued thanking the landowner for deciding to sell the land for a price welll over waht he originally paid for it. Generally the term "greenmail" is applied to the technique.
The Success Pond owners have a deeded right to access their camps via the road, but I do not know if they have specific right to access via the Berlin end. I believe that at least a portion of the land along the road on the Maine side is owned by a different landowner and therefore I exepct access may be obtained. Of course I believe there is one major water crossing that needs to be maintained from the Maine end of the road that at one point had washed out and blocked access from that end. The road rapidly degrades unless there is ongoing maintainence, no one knows what entity is going to maintain it once the logging stops, I expect after a few seasons of neglect, driving on the road with passenger vehicles will be a non issue.
With regards to the "legal" off road use of the road by OHRV's, contrary to what is currently occuring, the majority of the road is specifically posted from OHRV use for a majority of its length with the exception of the first mile. The reality is that many OHRV's use it as a race track. On most weekends it is a fairly dangerous place to drive as there are all sorts of vehicles flying down the road at unsafe speeds oblivious to incoming traffic. As there appears to be minimal enforcement, I expect the use of an licensed on/off road bike to circumvent the gate would be an interesting loophole. At a minimum the on/off road bike would need to be dual registered as an OHRV and a road legal bike to legally access the Berlin end via the OHRV trail.