Smoke trail Charlie, welcome to the tread, or as they say in my adopted country, "Bienvenue aux Fil!" You'll find plenty of experienced help here.
I agree with acdii that an LT40 would be a good choice for a trainer but may I offer three alternatives, the Telemaster 40 and the Sig Senior or Seniorita.
I used to import Telemasters into Europe. I still have three but two of them are awaiting attention. They are easy to fly but their detractors would say that they tend to float on landing approach. I say it's just a question of getting used to their flying characteristics!
The Senior and Seniorita are the same model, the Seniorita just being a smaller version of the Senior. What is different about them is that they are three-channel models, they do not possess ailerons. I have found, over the years that an elderly beginner is often better off with a three-channel model because they are automatically stable in the roll axis, I'll concede that once having learned how to fly a three-channel model, the beginner then has to learn how to fly with ailerons. On the other hand, it appears that you can already fly a helicopter, so orientation should not be a problem for you and in these days of buddy boxes, you should be alright with the Kadet LT 40 which is available both as a kit and as an ARTF.
Your choice but I wouldn't recommend a Piper Cub as a trainer. They are not quite so easy to fly as appears to be the case. Keep it as your second or third model.
Happy Landings