Nature Valley, the folks that bring you granola bars and more, now offer a virtual walk along trails in our National Parks. Check out the interactive website http://www.naturevalleytrailview.com/ where you can pick, for example, the Grand Canyon and see what their famous trails look like if you were hiking them. Better yet, using Google's 360 degree cameras you can look around for your hiking vantage point. Much like Google does with its street mapping views.
Maybe this is the next best thing to being there? Nah. But its a cool idea.