We have built them both little places to hide but they don't hide when we are around. They mostly stay at the side of the cage where we are nearest to and give us sad... hungry eyes. My Russian will bang on the side of the tank to get our attention if we ignore her long enough.
I want to do something different with them and build some sort of an island/central cabinet system with a tortoise table of sorts of top, but I haven't gotten a good plan yet
Here is one of mine, a friend built it, 5' x2.5' x 18" high. Completely rearranged since then, but you get the idea. He overwintered here, currently he is outside more.
view of the main area (not using clamp lamp now)
view of the second level, where he eats (now I use newspaper).