My wife has a conference next week (July 16-18) at the Gaylord National Resort just south of DC... my parents are coming with us and our 9 month old. We (my parents, baby and I) plan to spend 1 day exploring DC with the baby while my wife is at her conference... any recommendations?

Will be first time for all of us. Having the baby is obviously going to limit us but I'm mostly looking for recommendations on how to get around (Metro vs Hop on/off tour busses??), and then like 1 or maybe 2 activities/tours to book in advance. Otherwise our day will be flexible and we'll just go with the flow. Recommendations for places to eat or not eat also welcomed!

In addition, I mentioned we're staying at the Gaylord National Resort so any recommendations in that area that are not in DC would be appreciated! Alexandria, VA across the Potomac River I hear is nice.

And then once my wife is done with her conference, we're renting a car for 1 day to drive far away from DC and see more of the rural area... this day is my wife's responsibility to plan but any suggestions on which direction we should go and place to see would be appreciated! We likely will end up at a winery haha

Thanks in advance!