Taking the two examples in the subject line:
NLR (I assume you mean Northampton & Lamport Railway) was a pleasant enough ride for me. It met all expectations; we went for a ride on the full route and got a ride on the full route with no fuss.
Rushden was very different (three? years ago). The website said trains would be running. Getting there was an 'event' for us and we had a hotel stay nearby. We turned up and saw no evidence that anyone was even planning to run a train. We asked a volunteer who was wandering past and he 'thought' they 'might' run something that day. Nothing happened; another volunteer said later that the regulator had banned them from running anything so we left very disappointed. Fair do's, though. I followed up by email later and the 'trains running' claim on the website was removed.