Totally agree with this substrate mix! Make it quite deep in different areas and sit back and watch the fun commence!! If you turn your back for 1 minute you'll be playing hide and seek your tortoise will be the winner! You can always put some Timothy grass in the hide but you'll notice your tortoise won't miss it!
What do you feed your tortoise? Do you supplement with vitamins or calcium? I know you have had your tortoise since you were a little girl... love the pic you posted in one of your other threads.