The Grand Canyon Railway, great for children of all ages.  Leaves daily from Williams Depot to the Grand Canyon Depot just 80 steps away from the rim.  Complete with cowboys and strolling musicians. 

The Grand Canyon Deer Farm located 10 minutes east of Williams on I-40 great for children. 

Planes of Fame Aircraft Museum and Bedrock City/Flinstone Village are between Williams and the Grand Canyon, 30 miles from each on State Rt 64 at Valle, at the junction with US hwy 180.