G-Spot: I think the solution is not to throw the entire U.S. body of property rights law and tradition away because you or I want access. Let's keep private property private. (I certainly agree with requirements not to degrade the "commons" thu action on private property.) Furthermore, my rights don't depent on what reason I cite when I close my land to access. That is, people don't have to be littering my land for me to post it, and I shouldn't have to let them in if they do everything right. I consider the highest value of my property to be its solitude. I simply don't want to meet anyone there--I have to interact enough with people at the airport, the office etc. etc. My land is more like a living room to me than is most people's living room. I searched long and hard for land that would provide that. I have stream front, but it's too small to really fish (it has fish). I didn't buy land where there would be tresspassing hassels, like a fishable river, because I don't want those hassels in the too-little time I have to enjoy the solitude. But the guy who did buy such land has the same rights I do.
So what of access? We need to get access on the free market, without diminishing anyone's rights. There are many organizations that do that, and I am on the board of one of them (a local land trust). Land aquisition is one way, but a conservation easement is a lot less expensive. We have found that people want to conserve land and they want other people in the future to enjoy and respect that land. They give away land to trusted organizations to achieve those goals. Not enough access? Well, then we need more people to get active in the organizations that do the work--and it is a lot of work.
Concerning ownership and resource conservation: the very best and ther very worst conserved land is in private hands. We are very lucky to live in a part of the contry that has significant public lands and waters. Texas, by contrast, is about 95 percent private. If you want to hunt you pay at least a hundred a day, and $10,000 or more for a season of deer hunting on good land. Washington is a lot more like Switzerland than Texas is like Washington. In Texas you have to be rich to hunt, there is little public land to get access to, and the ultimate is to own a ranch. The resource? The state is crawling with game.
So, access yes. But we need to achieve it through ownership and easment in the open market. Property rights? Yes, without a doubt. But any owner who degrades a riparian corridor or loads a river with nutrients or sediment gets no sympathy from me.