If you stay too far out of the city, you will regret it. I commuted on the DC metro for years, and during rush hour, it is not pretty. If a train breaks down, you are stuck on a platform with lots of aggravated commuters. Even without a train broken down, the Red Line is SOOO crowded during rush hour.

I think your niece would like the activity of Dupont Circle. Lots of great restaurants, book stores, always stuff going on. I stayed in Feb at Victoria Maxwell Art Studio B&B in Dupont for a very reasonable rate and loved it - it was so safe, tons of people out all the time. Some people may try to scare you & say that it's a gay hangout, that may be true but I never would have guessed it from my stay.

Yes, you can stay in Rosslyn, Crystal City, etc. But don't stay in New Carrollton, my goodness, there's no need at all. One place that's a little further away than I would like, but would still work, is Alexandria. If you get something close to the blue line, you will have easy access into the city as well as to Old Town Alexandria, which is a lot of fun - shops, restaurants, etc.

Attractions - Smithsonian is fantastic, the (free) museums can keep you busy for days. What are your niece's interests? If she's a nature or animal lover, definitely go to the national zoo - free and excellent. Spy Museum would probably be very interesting.

The key is to stay not far from a metro stop. Anywhere in Bethesda around Wisconsin Ave is nice. Since March isn't such a popular time to go it should be fairly easy to find a hotel around $100. Try Holiday Inn in Rosslyn, VA, the subway isn't that far away from the hotel, can't tell you the rates though. Holiday Inn there might have a pool.

If you can time you stary in Washington for a week-end (beginning on Friday night) you can get excellent discount rates at most hotels.

Also, try this web site:

http://www.capitolreservations.com/

Hi,
If you click on my name I have posted a D.C. trip report this month. It my be of some help. Have a good trip.

>> Also, I'm trying to teach my niece how to use this sight and showing her how HELPFUL fodorites are.<<

Fodorites are indeed helpful and the suggestions that you do basic research on this SITE is good advice, and not a slam. Then, come back for more specific questions. Your questions in your OP are very generic in nature and there are a multitude of posts that can give you a start in your planning.

Modeling the research process for your 12 year old niece can be one of the most effective things (and a life lesson) you can do for her as an aunt. Let the info that is already here picque her interest and help narrow down choices of interest to her.

Enjoy the research!