We will be visiting in the middle of my son's cross country season. I'm pretty sure the coach will expect him to run while we are there. There will be a treadmill at the hotel, but he isn't used to a treadmill. Are there any paths that are good for running near the parks, or is it generally too congested with traffic? It would have to be someplace he would be safe going alone because none of the rest of us can keep up with him. 
What time to security gates go up in the morning? Maybe a large loop around DCA/the Grand?

What time to security gates go up in the morning? Maybe a large loop around DCA/the Grand?