Thing is - when the pain hits I wouldn't really be able to drive the scooter either.
As in; not a safe option. Results; other mobility aids to reduce the symptoms and still offer a place to rest on the spot. Most commonly used options; wheelchair or a rollator (walker on wheels with a seat on it)
It had never been a problem bc the kids needed the break too - but the older they get - the less they need them.
I suppose they could just go ahead and I can meet up with them.
If you don't want to use certain options that are out there, that is your choice. Not a smart one, IMHO, but it is your right to make one. Which would indeed result in the 2 above being one of few left out options. It's up to you which one you'ld rather do.
One way or the other, you are the one here making the problem bigger than it is. You don't want to use aids that are out there to makes things easier when needed nor do you want to "be a burden" to the kids a.k.a. touring on your pace. Something has to give, you can't have this cake and eat it.
Take it from a daugther of a father with SA amongst others; you'ld be seriously cheating yourself when letting those fears and dogmas rule your Disneytime. We couldn't have cared less for the moments that we'ld break on a long day amusement park. It simply was one of the things that would happen, simply enough because it was parently ordered it will happen. No biggie. Dad wouldn't be able to do certain rides; so it is, no biggie. Just like mom wouldn't do a rollercoaster without being forced.

It simply is what it is. Not only was it nothing but logical sence to tour in a way that was doable for all, it was a good IRL lesson in one of the many values they were installing in us; not just focussing on ourselves but also on our loved ones, taking care of loved ones where needed etc. Not once did I feel cheated because of him happening to have SA on such moments. Simply because I wasn't cheated. We'ld be doing things as a family, enjoying them, having a good time, each simply being who the are.
The negatives? Cheated is too big of a word and even a Dad is alowed to be human every once and again

but what would stand out negatively? Those few moments where dad would be such a stubbornheaded mule he'ld refuse to come along at all because of his stubborn pigheadedness "I do not use a mobility aid" and alikes. He'ld knew he wouldn't be able to do a whole day in a way he considered it would have to be -for whomever or whatever- and as a coping skill simply stay home. Not only do you miss dad being there, you totally pick up on the mood and reason of why. You pick up on the negative emotions and even if you might not be able to understand them. When he is there you know one is in misery and thus all are in there to some extend, he didn't lead by example. It took him way too long to listen to me (only one in the family he will listen to when it comes to medical stuff as he values my own experiences), docs and physical therapist before he decided to "give into" getting a rollator. Took a lot more pressure before he'ld use it. The result? A large smiling man that outruns others again, walks distances upto 10-20! times more than without, has loads of less pain afterwards and himself grumbles like Grumpy himself that it might've been smarter to have done this sooner. Oh, and let's not forget his much better mood being a nice addition when being out together and no longer having to see him cheat himself out of things or have unneeded pain.
The difference for me was totally made by how he would deal or not deal with things. No biggie for him; no biggie for us. Him making a biggie, being stubborn or feeling misplaced guilt? Bingo; we'ld pick up on it. Those were very few moment when we were young kids, but I can still paint each detail of it. Where as those 99% other moments? Actually actively have to think about "how did he do that and how did we react to it" as it's not an active memory for me. Those active memories consist of my dad simply being dad, being a great one. And after some second; oh yeah, and he already had SA which was why he didn't work that much, visited the hospital so much and couldn't physically do everything with us like some dads.
Another thing to think about; seating. Depending on the exact location of the inflammations/boning up of the chest you can find almost all standard seats found around the parks for both shows and dining to be..... well..... torturous. Having a proper back on a seat makes a huge difference. Same goes for benches (used at many shows) which can be an extra hardship for the chest when coming back into movement after a show -which not all with SA are aware off when not that tuned into what causes their chest aching yet-. With the use of a mobility aid, you can control this and make sure it is a seating that doesn't cause more pain or can even be a reducer. I would aim for usage of your "own" aid when going for this. Simply because you'ld have to try out before to see what comforts and aches your chest area. Doesn't always have to be something you actually own, but could also be a specific type and brand of aid you can rent locally. Read; try out stuff at home way before trip to see what works for you and from then on only rent said type. With onside rental it is almost impossible to do this without it impacting the Disneytime.
Not an option? Next best can be a standard rental but with your own cushion and/or backcushion. Those are less expensive to own and are multifunctional. Can easily be dragged along to for instance a friends house for a party when you know their chairs aren't comfy enough for you.
I might be a bit confrontational, but stop worrying about cheating the kids! Make a choice that suits your needs and wants (and be honest with both

) and go with it. It is what it is, there is nothing wrong with that. In fact; it will result in you and family doing Disney in the most optimal way possible instead of cheating not only the kids but also yourself out of who knows what.