On your way to Takakkaw Falls, be sure to stop at the highway overlook for the Spiral Tunnels of the Canadian Pacific Railroad. The signs tell you about the railroad history of Kicking Horse Pass and you can watch a couple of trains circle through the tunnels. You can spend as much or as little time as you want and it's fascinating, even for kids!
We also enjoyed our hike up to Johnston Canyon falls, although they don't start to compare to Takakkaw Falls.
Almost forgot: don't miss Maligne Canyon while on your way to Maligne Lake. It is a narrow, slot canyon carved into limestone bedrock with many waterfalls along its relatively short length. You won't see anything else like it on your trip.