Rescue to therapy

In January, we came across a dog that had been hit by a car lying in the middle of the road. Of course, we stopped and with the help of another person who stopped after us, we moved him to the side of the road. The gentleman who helped us said he thought he know who the owner was so he took off to find him. In the meantime, a woman and her brother walked down from a nearby house and said she didn't know the owner but the dog had been living under her porch for a month or so. The previous man came back and said he thought the brother was the owner but apparently not. So we asked everyone there if they minded if we took the dog to the vet and they all said it was fine with them.

Long story short, took it to the vet = heartworms and both front legs broken in 2 places. Currently treating for heartworms, casts came off legs this past Tuesday (he was the star of several campgrounds while they were on!) and now I'd like to start his training as a therapy dog. Is it possible to have a traveling therapy dog? Could we call a local hospital wherever we are and ask if they'd like a visit? Does this sound plausible?

He has never barked or growled even when they were setting his legs. I can take food away from him and he doesn't say a word. Part lab, part I-don't-know-what but most excellent temperament.