To successfully plan a family vacation, especially with young children, it's essential to build stamina and practice walking distances beforehand using a fitness app like Runkeeper. This helps account for factors like stroller navigation, crowds, and unexpected meltdowns. By training in their neighborhood and simulating the actual routes they'll take on the trip, families can better estimate travel times and make more realistic plans. The app's features, such as logging activities and rating workouts with smiley faces, also provide a fun way to engage kids and capture notes for future reference. Ultimately, the prep work paid off during their Parisian adventure, allowing them to enjoy the trip and create lasting memories.