Our 2014 law predates class ratings. The law states assisted bikes are allowed to be ridden on roads and bike lanes and the power limit is 750 watts (1 horsepower). Assist can be pedal assist or throttle or both. A lot of people (including myself) thought as long as an ebike was within the power and speed limitation we were legal to ride trails, paths and park land. We were wrong.
When in 2015 the 3 Class law was proposed for the first time in California it excluded all off road venues. Trails and paths needed to be approved by local governments. It specifically states that in the law. Most every state that took up the law just copied it word for word. People for Bikes is behind the movement across the country. Some states added more restrictions, but as far as I know no state relaxed the restrictions. The law never included off road.
States that legalized ebikes for on road and bike lanes started to write formal regulations for off road. There's a long way to go. Many county governments consider their motorbike/motor vehicle laws cover ebikes. That's what happened in York County. In 2019 we were told ebikes were always illegal on county owned land.
Not to go into a year long story, we won our access for Class 1 only. It helped that the state legalized Class 1 off road on state land. Those of us that like to ride trails, rail trails, canal towpaths, fire roads weren't done any favors by the 3 Class law. It specifically excludes off road in writing. That was too big a battle for People For Bikes. Locals have to fight that.
To make a long story short, Class 3 bikes are illegal everywhere in Pennsylvania right now. If we get the 3 Class law it won't include any off road. County government is responsible for most trails unless it's a private trail. We do have at least a few privately owned rail trails. Many counties haven't passed new laws and assume ebikes are illegal off road. Some haven't taken up the issue and a few legalized them.