In your province it's 20 years, at least when it applies to Crown land; and must have occurred prior to 1976
How to apply for a “squatter’s rights” grant Completing the application Declaration of applicant Individuals in support of application Application...
www.gov.nl.ca
This negates your theory for New Hampshire;
One of the oldest doctrines in property law is known as adverse possession which is the taking of title to real estate by possessing it for a certain period of time It allows a party to obtain ownership of a piece of property without having a deed. Adverse possession is most frequently seen in...
www.nashualaw.com
While Mr Lidstone has been there for 27 years, he states that he had permission. That destroys any argument of adverse possession.