
My husband has COPD too and uses a mobility scooter. My two Cairns got used to being walked while my husband was on the scooter very easily and very quickly. I think the "training" required took all of five minutes.
With the scooter my two dogs used to automatically break into a run when they got close to home - they figured out that the scooter could keep up with them and apparently they enjoyed a final sprint back home. Something to do with the dog treats they get after a walk, I expect. :-) Rudi is a wimp and if something frightened him - like a noisy, big truck passing on the same road - he would jump on the foot rest of the scooter and ride the rest of the way. :-)
Another lady where I live also walked her Yorkie and her daughter's dog (lhaso, I think) while she was on the scooter. Both of them were also inclined to sit on the footrest when they were feeling a bit lazy too!
I saw an eldery man walking his Yorkie while the man was using the scooter. The man had actually positioned a dog bed on the scooter's foot rest. Talk about plush and pampered.
BTW ... I think the message here is that dogs like to be chauffered around, so probably not a good idea to introduce them to the foot rest.
Husband's COPD is getting worse (he still smokes, arghhhh) and with the cold weather I'm doing walkie duties now, but I am not capable of sprinting and I expect they miss their "scooter walks."
Oh ... you obviously cannot use a short lead because the dogs will need to be a bit farther away from you than they would be if you were walking without the scooter. My husband and everyone else I've seen has used extendable leads, but I'm not sure if they are absolutely necessary... just a lead with a little bit more length.