Haven't read all the posts- but I see you're still active here.
We were there last July -
We stayed @ Wardham Park hotel - the zoo metro stop & then one of the Marriotts in Crystal City. Of course Crystal City was the closest in.
As far as food, we took a whole suitcase of food with us - enough for 2 meals a day. We had lunch in the hotel (wasn't included) & then packed 1 other meal that we ate on the mall every day.
Make sure since you're limited on time really plan your days well so you know exactly what highlights you want to see & what you can skip. We didn't get anywhere near seeing it all & we were there longer.
I'll tell you our absolute favorite thing we did was
www.Bikethesites.com
we took the monument @ nights tour the 1st night we were there - it was FABULOUS! Well worth the $$ the kids were begging to do it again. And it got the monuments out of the way so we could do museums.
don't forget to order online your tctks to go up in the monument & for Ford's theatre that'll keep you from standing hours in line when you get there
IF you have any questions you can shoot me a message - I'll help ya if I can