Great stuff. I did the same few years back, just in reverse. It is impressive that your kids 10 and 12 managed it -- congrats!
Next time you are ready for some more ambitious stuff. Awesome 3 days, 2 night backpack can be had by descending on Hermit, traversing Tonto and hiking up on Bright Angel. This is view from Monument campground on Tonto trail:
Even better, with proper logistic planning you can plan Rim to Rim in single push - without need for Phantom Ranch reservation nighmare, North-South direction preferable. Check this for some ideas: