My take is that we already pay for the land with our taxes. You don't feel that all should share the burden but we don't get to choose where our taxes go. We all pay for services we don't use. For example, there are no fees for the boater to take his boat through the ship canal opening up bridges and going through the locks. Until Eyman came along, our taxes were subsidizing the ferry runs. There are countless other examples of our taxes going to benefit a specific group.
And honestly, no, I wouldn't pay $5 per visit to a trailhead even if I did think they were doing $5 worth of work there. I already pay the salaries of the people doing the work.