STYLETHREAD -- LET'S TALK SHOP!

So I'm thinking about going on a day trip to DC in a couple weeks with my school. They take students down to DC, drop them off in the morning and then pick up later that afternoon.

I have been to DC numerous times with my family when I was younger but I'd like to go to some of the history/art museums (I've been to the Air and Space Museum and the Holocaust).

I’m looking for a plan of action of where are some of the best places to go and how to manage my time (such as exhibits that are up temporarily and is a must see). I’d definitely like to go by the White House (not in for the tour….just in front) and maybe Lincoln/Jefferson Monuments and the Capitol.  

Also, is it possible to venture out of the Smithsonian without taking the metro to go to a restaurant/café?

Thanks for any suggestions!

(I'm also posting this in the general chat to get more traffic)