Check the weather forecast. Check animal warnings or restrictions within the area. If you are traveling through the parks and hiking it is strongly suggested that you purchase bear spray and bear bangers to help protect encounters with wildlife. Dress accordingly for the weather and pack extra clothing especially for your child, as Canadian Rocky Mountains weather is very changeable.
Hold onto your child so they don’t trip, stumble or fall. There is a guarded fence to help keep people safe. Keep an eye on your children and animals. No matter how busy it is, there can always be a chance to encounter wildlife. Do not try to get close to any wildlife. Always carry bear spray and make noise to let animals know you are there. Pack in/pack out all garbage, as there are no garbage
I would recommend during the weekdays as it will be less busy. Trying to aim for an early start (9 a.m.), which will give you plenty of time to walk in and have snacks or lunch at the falls.
I would recommend during the summer months.
Purchase snacks and food in the larger cities like Calgary or where ever you start your trip. The groceries will be significantly cheaper, along with filling the vehicle up with gas. Alberta, in particular, tends to have cheaper gas prices.