Is there anywhere left in this area where a person can sit and not have to hear car noise?

I certainly doubt it. I think it would be nice if there were a spot.

Parks near my house are right along the freeway or surrounded on all 4 sides by little streets, i.e. the middle of traffic squares or circles. When I trek to the prestigious NW area there is a big park named Rock Creek, but it has a highway, parkway, running through its middle. Roosevelt Island offers a chance to get away from cars, but it's surrounded distantly by two freeways and it is in the flight path for National Airport.

There are nice bike paths along the parkways, but you're riding alongside traffic. There are picnic spots there too.

The closest spot I know of is along the Chesapeake and Ohio Canal in Great Falls park, in VA or MD. One must drive there, but once on foot you can walk pretty far from the cars. Once N and I were there in the evening around dusk and there were only people every 5 minutes or so. We saw a deer across the river and a big bird. Then we got in the car and drove back to the city.

Here's one of my favorite photos from that evening. This is along the Canal Towpath. The canal runs from far North of the city, through its heart. You can walk along it in Georgetown too.

Ok, off to enjoy my morning now. Just needed to get the traffic noise gripe off of my chest.