I also have a 6 year old with ADHD/autism and similar energy/mobility issues. We tagged his stroller as a wheelchair and used it in queues (very handy if your child has elopement issues or if he needs a peaceful space to hide and decompress! Just in case you weren't aware that this is something you can request). When asked if he was able to transfer, I always said yes and just carried him and set him down in the ride seats, especially for the moving walkway rides. I already was dealing with anxiety about the judgement we received from some other guests about using his stroller in queues, so I don't think I would have been able to deal with making them stop continuous rides for me to load him (I personally would never judge anyone for needing that accessibility measure, be we encountered some shockingly judgemental guests on our trip last month!), but he's small for his age and I'm very tall, so it was easy for me to maneuver and load him myself!