I agree with nepali american.

I would def metro it into the city because parking can be a pain in the a^&.


Out of all the Smithsoniams I think I would reccomend the Air and Space Museam which is on 7th street..

I would end the night at the W hotel on F street and have a drink at the rooftop bar. Awesome view of the monument and also the White House.

II hope this helps! Please let me know if you have anymore questions!