If local, something I have done for multiple family members over the years is book a pedicab tour of the monuments, esp a nighttime one where it’s all lit up. They bundle you up with blankets and even my mom who is a wimp about the cold said it was cozy and a lovely experience. You could go with her or if the kids are older they could go with her and you could all do hot cocoa after.
We used this company every time:
https://www.dcpedicab.com/en/mobile
We’ve had a few different guides but the best one is named Donald Clark. He’s a high school history teacher and this is his side hustle so he’s super knowledgeable about the history of the area and great at sharing it in an interesting way.