It's a few year back now, but I did a mini trip just three nights and two days. It was so much fun and I was amazed at how much we did get done! I'm not a fan of heat and humidity, so picked an October weekend when DS didn't have school on Friday. DH didn't come, but it was me, DS who was in High School at the time, my niece who was in college at the time, and my mom.
For planning I got tickets ahead of time from our congressional representative's office for the Library of Congress, the Capital Building, and the White House (I especially loved that White House tour -- the photos they had of previous presidents and famous people all blown up was so much fun to see. When we were there there was a big hallway with all of these to see upon entering.). They arranged all these tours, so they would be convenient time wise for us to fit into one day while we were in that area.
I found Washington DC hotels to be really pricey, so to stay in budget got a room with the triple deal (free parking, a nice buffet breakfast included, and double queen room) at the Hilton Garden Inn in Bethesda, MD that was right near the metro. Sure it took us 20 minutes or so to get places, but places right in the city of similar quality were more than double the cost. We used the metro to get everywhere and it was very easy to use and convenient.
DS and I coming in from St. Louis got an evening flight into Regan and took the metro to the hotel. My mom and niece coming in from Chicago flew into a different airport and rented a car that they parked at the hotel for the weekend for the most part, but with the deal that they got and the fact that we had free parking it was cheaper than taxi/uber.
Day 1
We did the Library of Congress Tour, visited our congressional office, visited my niece's congressional office, did the Capital tour, and then did the White House tour. The weather was just beautiful and Washington D.C. is so gorgeous, I had that song from Wicked, "one fine day in the emerald city" going through my head. Next we went back to our hotel and relaxed a little bit and had dinner. And then for the evening we did the "Monuments at Night tour" -- of course you can see all of these for free if you have the time to do it, but with our limited time, this was great, having the bus take us from monument to monument and give us the history too. It is a fantastic option if you have limited time. The only monument which I personally find very moving that I would have liked to see my son and niece to see that wasn't on the tour was the Vietnam Memorial. It's probably not one to see at night as this is not one that is lit up and more of one to see during the day.
Day 2
We let DS have his top picks for 1/2 the day and my niece have her top picks for 1/2 the day, as there is just so much that is worthwhile that it is hard to pick and choose. Day 1 had been my must dos for them to see. For DS who is a Titanic Enthusiast he wanted to see the Titanic memorial which is in a pretty park that locals do a lot of jogging in etc. This is where James Cameron got the idea for the "King of the World" pose for Leonardo DeCaprio in his movie. This was tons of fun, but not something anyone other than a hard core Titanic enthusiast should bother with. Next we hit the Air and Space museum (of course you could spend tons of time at so many of the wonderful Smithsonian museums), but on our tight timeframe we only had time to maybe spend an hour and a half / two hours at one. DS was very happy to set to go here. Next we headed to Arlington, as my niece really wanted to see Arlington cemetery.
Departure Day
After breakfast DS and I took the metro back to Regan and flew home. My mom and niece had a later flight and I believe after checking out took the car into Washington D.C. and went to see some other monuments that we didn't see on the tour or ones' that my niece had wanted to see again.
Note: This was my fourth trip to Washington D.C. and my mom has been quite a few times before. This was the first trip, though, for both my son and niece.
Just want to say that I remember this trip very fondly and we all do. Even if you can go for a short time, it is so worth it.