But my question is how much does it entail for paperwork and exactly how hard is it to do it? or does it depend on each state?
The therapy dogs organizations (TDI, Bright and Beautiful, etc) are private organizations and have no government connections. In addition to testing and certifying, they provide a blanket insurance for teams visiting facilities and performing therapy work. Liability is obviously a concern for these facilities. For that reason, most of them will INSIST that a visiting team be sponsored by one of the recognized therapy organizations.
The paperwork involved is really quite trivial. Much more significant is the therapy dog test itself and even more so the training to take the test. Many therapy dog organizations conduct their own testing. The tests are generally similar to,
but not the same as, the CGC test, so it's important to know the specific requirements of the organization that you are interested in. A few organizations do use the CGC tests themselves
How hard it is depends entirely on the personality of the dog and the handler. With a mild-mannered, relatively laid-back dog and a conscientious handler, preparing for the test is not much more involved than preparing for the CGC test. With a high-drive, high food-motivsted, boisterous dog, even a conscientious handler will find the test a challenge.
As for general breed characteristics, the one thing you often have to work on with Great Danes is their predisposition to be quite suspicious of strange people approaching them. Most of the therapy dog organizations require that the dog be not just tolerant of strangers, but be
VERY accepting of strange people touching , petting, and even hugging them. That's one way the therapy test differs from the CGC test. Once you can get that suspicious predisposition under control, they usually make good therapy dogs - assuming, of course, the handler is willing as well.