Family fitness is an exercise in wellness. It is an investment in the overall health of your family which includes many aspects of wellness such as physical, emotional and social. I always find that it takes incredible mental effort to get the entire family involved in my workouts. To run with the stroller I have to dress the baby for weather, pack supplies, deal with a helmet, and stop to deal with fussiness. Add to that a dog alongside, navigating a leash, picking up poo, slowing down for pees and sniffs, reigning in to pass other pedestrians (especially those with dogs). Going swimming with the kids is a comparable ordeal of planning, packing and executing. Bike rides are slow and involve playground or library pitstops. It certainly is tremendously more difficult than getting dressed, grabbing my own gear and heading quickly out the door on my own workout schedule.
The interruptions involved with family fitness deter the intensity you can achieve with solo training. I certainly cannot swim laps with my kids so I find other exercises to do in the baby pool such as floating knee crunches with twists, floating finger pushups, and simple side hanging leg kicking. I think running is the exception because what you sacrifice in speed you compensate for with resistance (stroller). It's a different workout, but comparable.
No matter, family fitness should be one of your top priorities in my humble opinion. Getting everyone active IS our role as leaders of our families. Use the challenge as a mental exercise in coping with stress and developing management skills. Prepare yourself mentally accordingly. Just as you would warm up for an exercise session, warm up mentally by planning your excursion- make lists, pre pack and try to set yourself up for success! Expect it to be challenging, as you would any other workout, and then just get it done! Your family will thank you for it. You will build healthy bodies and healthy memories both to last you your lifetimes!