Some Long Weekends in Philadelphia

I'm lucky enough to be working from home, but wishing for a vacation, decided to take a few 4 day weekends in places that would make great easy and fun trips for kids, in preparation of motherhood. Philadelphia is a great place to start. The original home of Congress and the President, it was where everything started. Many of the homes are 300+ years old, so you can feel like a time traveler. There is the first Post Office in the USA, still in business.