Sounds like you have the itinerary set - one last suggestion - if max efficiency is your goal, i would go in roughly the following order.

Lincoln / Korean / Veitnam / WWII Memorials

Washington Monument (just walk around outside it)

Natural History Museum

Ford's Theater

National Portrait Gallery (optional)

Archives

Native American Museum (optional)

Air & Space Museum

Leave for Airport from LenFant Metro Station 1.5 blocks from Air & Space (corner of 7th & Maryland)