If you want to see some nice scenery, take the George Washington Parkway west from DC. The Parkway runs along the Virginia side of the Potomac, which is one of the prettiest rivers you will see. The overlooks also have nice views back toward the city. The Parkway ends at the Beltway, which is to be avoided at all costs, but the exit ramp for the Beltway will take you to Georgetown Pike (Route 193) without ever having to get on the Beltway. Take Route 193 west to Great Falls National Park. Spectacular (in my opinion) water falls and rocks to climb around on. Especially nice if the river is up. While you are there, look for the poles marking the high water marks from major storms over the years. The amount of water carried by that gorge boggles the mind.

If you avoid rush hour (and you definitely need to do that) the round trip will take less than an hour and half, not including stops of course.

The town of Great Falls is a couple miles further west. Several good lunch/dinner opportunities there.

You might also look into visiting the Maryland side of Great Falls. When I was last there, you could not see the Falls very well from the Maryland side because the footbridge had been washed out, but that was 25 years ago. I don't know what it's like these days.