The bike trail in this park was one of the first rails to trails bike paths ever, and is the best bike path I have ever had the experience of riding along. It is gently graded and goes through pretty woods, next to beautiful streams, and over some really heavily used freeways.
In September of 1995, my father and I rollerbladed the entire 45 mile bike trail. We convinced my mom to drive us out to Purcellville, and then we started rolling home to Arlington. It took forever. We stopped in Vienna (mile 25 of our trip) to eat lunch, and then sat around for a while convincing ourselves that it would be a good idea to get up and get back on the trail. In the end, it took us almost 8 hours. When we got to the turnoff for home, we realized that if we went another 2.5 miles down the trail, we would have done the entire thing, so we did it! Unfortunately, we hadn't properly considered the fact that we woulld have to come back those 2.5 miles. 5 miles later and one "end of the trail" celebration later we were at the turnoff again. Then, we did a very stupid thing:
We sat down.
We simply could not get up. We were approximately half a mile from our house, we had completed (literally) 99% of our herculean task, we were near-supermen in our own minds, and none of that mattered. So we sat there. We tried to force ourselves up, but in the end it was only the last dregs of our combined machismo, coupled some help from sign post we were sitting next to that enabled use to roll home triumphant. To this day, it is one of the things that my dad and I trot out if we want to feel more hardcore than we actually are.
Although it took a while to recover from, it was extremely rewarding. If you are feeling bad ass then you should try it, with the caveat that you musn't sit down when you are less than two miles from your goal. Just keep going; you'll get there faster, and "there" is air conditioned.