I don't know anything about your health situation, or your overall condition, but every idea deserves a bit more than 24 hours of discussion, no?

Maybe I'm being incredibly simple, but if hills are the issue, is it not possible to avoid them?

It seems to me that the most important factor is already in place - a well trained dog. No amount of conditioning or gearing will compensate for a dog that can't be trusted.

Of course, it's your decision. and I mean no disrespect. As someone with a similar dream it hurts a little to see the idea dismissed so quickly.

In any case, the best of luck with your touring!