Bob,

If you are referring to US 15 and not PA 15 then it is not that bad of a route. You will pick up US 15 in Carlisle and take it down to 270, which puts you into the DC Beltway.

I usually avoid this area when I am going south and try to go around. You can take US-15 even further south and then take US 17 near Warrenton to Fredricksburg, MD. This eliminates a good portion of the DC traffic, and puts you one hour from Richmond. Very pretty trip with little traffic (for the DC area). I have timed my trip from Pittsburgh to the OBX and found that if I take the secondary roads which include US17, it goes faster and it is a more relaxing drive.

I have taken US 15 to Leesburg, from I70 and it is really easy and quick. I 270 is usually hit or miss and the same with the beltway.

I do not have the nav in my car so I am not sure how that would work in the car.

I did this on Mapquest to avoid the beltway (not sure how to do that on google maps).

http://tiny.cc/37tBp

Of course just my $.02

 

And of course the avoidance did not come though on that link.

so here is the detail from the mapquest:

9: Merge onto I-83 S via EXIT 70 on the LEFT toward SOUTH HARRISBURG/YORK.9.4 mi10: Keep LEFT to take PA-581 W/HARRISBURG EXPY via EXIT 41A toward CAMP HILL/GETTYSBURG.2.3 mi11: Merge onto US-15 S via EXIT 5B toward GETTYSBURG (Crossing into MARYLAND).68.6 mi12: Take the US-15 S/US-340 W exit toward LEESBURG/CHARLES TOWN.0.1 mi13: Merge onto US-15 S/US-340 W.4.6 mi14: Merge onto US-15 S via the exit on the LEFT toward LEESBURG (Crossing into VIRGINIA).17.2 mi15: Stay STRAIGHT to go onto US-15 BYP S/LEESBURG BYP.4.3 mi16: Merge onto US-15 S toward WARRENTON.24.4 mi17: Turn RIGHT onto LEE HWY/US-29 S/US-15 S. Continue to follow US-29 S/US-15 S.15.2 mi18: Turn LEFT onto US-17 S/MARSH RD. Continue to follow US-17 S.26.8 mi19: Merge onto I-95 S toward RICHMOND.48.1

 

I love 15!
It's like an old fashioned drive through the country, back in the days before super highways.
I also prefer the roadside diners to the Maryland House or Vince Lombardi rest stops.
But to avoid the I-95 to Beltway corridor is the main benefit.

 

So do I, it is a great road south. No muss, no fuss and a beautiful drive.

 

Hmmm, I'll have to edit my google map to avoid the beltway...I saw it went through there but figured out well....I believe it is US 15 in PA.

 

Google maps has a new feature.
Drag the route to a preferred location and it recalculates

 

Yup, love it! That is how I got it match your's and the other's suggested routes.

 

Yes I figured that out too, pretty cool to be able to move the route around to avoid things.

US-15 is 2-lane and 4-lane in certain places but it does continue moving. I can't say the same for the DC beltway. .

Anyway, enjoy your vacation!