Yeah, the DC area is a miserable place to travel. It's got the worst traffic, only behind NYC and LA. Drivers get pissed off and have been known to threaten others with weapons.
The problem is the driving culture between Virginia and Maryland. In Virginia, you'll get pulled over for going 3 miles over the speed limit. Virginia cops are everywhere and will pull you over for anything. Therefore, traffic runs slow.
Maryland traffic is fast! Cops will not pull you over until you are doing at least 10 mph over the speed limit because judges will throw out anything less than that. So, traffic travels at about 10 mph over the speed limit. Never drive less than the speed limit in Maryland or people will get extremely pissed off. The traffic is horrible and people want to get home from their long commutes, so, people can get aggressive if you get in their way.
Though it is just south of the Mason-Dixon line, Maryland was a union state in the civil war, so, even 150 years later, culturally, Maryland is a northern state and there is a difference from southern culture starting right around DC, specifically, that the speed of life is FAST! People drive faster, talk faster and you're expected to work faster! Don't hold people up in the drive-thru, either, because those workers are supposed to get you in and out in a certain number of seconds! New York is even worse. The north is not for sissies!
Good luck on your trip. It sounds like a retirement dream!