Last I checked the Pentagon is only open for tours for school groups, scout trips and the like. That being said I have been a few times for meetings and is interesting to see.

For the White House and Capitol just contact your Rep or Senator; they will tell you what is required for the WH and can have a junior staffer or intern do a Hill tour for you.

Supreme Court is interesting and next to the Capitol so can be done in the same few hours and does not require reservations.

Never been to State or OAS in the 7 years I have been in DC.

I enjoyed Engraving and Printing when I went with family a few years ago; the tour guide was awful but it is neat seeing money getting printed. It requires a time stamp ticket that IIRC you need to get the day of the tour but I might be wrong.