My husband has recently starting using the book Training Hearts Teaching Minds by Starr Meade for our family devotions. It is based on the shorter catechism. What we enjoy so much about it is the length of time it spends on each question. It has very applicable short devotions for 6 days on one catechism question. We have had some great discussions with our 7 year old. We are memorizing the questions with her. I had never heard of the catechism prior to the last 6 years. What rich truth!
For pre-school age we used Big Truths for Little Kids by Susan Hunt. The stories are very age appropriate and concepts pre schoolers are able to grasp.
Have a good weekend