Hi Tony,
I'm still in the experimental stages, but a bit of nice soft moss with a few pieces of bark for your little ones to hide under is adequate. Having a layer of charcoal on the bottom will help absorb odors. You can buy aquarium charcoal at any pet shop.
Here are the evolution pictures of my set-ups:
Completely terrestrial, misted daily:
Terrestrial, with a small, shallow water dish.
Terrestrial, but adding a larger water section (water is only 1.5 inches). I took out the bark/shell since my little guy heads directly for it whenever it notices that I have a camera in my hand:
Er, so one thing that is bad about my set-ups is that I do have two pieces of marine shell (and I had more before). In my defense, they were weathered in a freshwater aquarium for 3 years and I did try a "cocohut," but given the choice, my torosa decided it liked the shell. However, do NOT put a spiral shell into the tank that your juveniles can climb into. (*coughs embarrassedly*) They like dark places and will not hesitate to "get stuck" in the shell.
Try to have a small dry section for them to go to. If you watch your animals, they'll clue you in as to what they prefer.