When I was unemployed and trying to feel better about myself, I used to do weekly nursing home visits with my little Zulu dog, and with a big ole Orange Tom cat I had. I organized a couple friends with good dogs to do this with me. The cat was the only cat I've ever had that would walk through a new place on leash without wanting to panic and hide under something. I used to be able to just plop him on someone's lap and there he'd stay.
I went to about four different facilities in Gig Harbor. Some would have me go room to room and look in to see if folk wanted to have a pet visit, and some facilities would bring the interested people down to a common room and we'd just let the dogs mingle the room.
And it wasn't complicated... they didn't require that my pets be certified as therapy pets or anything... Those places were happy to have the volunteer entertainment. Some watched me closely till the pets had earned trust and some took my word for it and let me go. So if you do have good judgment about whether your dog is well suited, it's really not hard to go do this, just call them and ask.
I am sure you brought a lot of joy to those residents...people often forget the elderly in nursing homes, and forget that many of those people have a pet that they had to leave behind, when they entered the nursing home...having visitors coming in with their pets, is exactly what these elderly need...