Hello - yes, this is tough. This is a long reply, because I really feel I can relate to your challenges. We have twin boys (now age 9), one of whom has cerebral palsy and uses a walker/wheelchair. He also had reflux, which was severe enough in his early years that eventually he had the anti-reflux surgery. It was very successful. He still has a g-tube (feeding tube) to supplement his nutrition, but he only has a night-time feed. I remember the days when he was getting about 75% of his nutrition by the gtube, and had meds before meals, upright after, etc etc. It's an all consuming process and can be very stressful.
The posters here are absolutely correct that a GAC is not a front of the line pass, which you know. However, I will also say that virtually every CM who met us on each of our 2 trips (1 to WDW, 1 to
Disneyland) went out of their way to try to make our vacation magical - for everyone in the family. Sometimes we were asked if we wanted to ride twice (Big Thunder, Test Track, partly because it's easier to get the wheelchair to the exit that way). Sometimes they were a little quicker on the child swap so we could move on as a family. CM's carried our food to the table when one of us was pushing the wheelchair. The ramp to board the monorail was pulled out as we approached, no need to ask for it. They just seemed to find little things that would help, and several told us "we can see that your family faces special challenges every day. When you're here with us, if we can make your day more magical, that's what we like to do." Yes, and that's a direct quote. It made me cry when they said it and I'll never forget.
Using the stroller as a wheelchair will help you get decent seats for parades and shows without the same waiting, and certainly you can avoid waiting in the sun. Would a pediatric wheelchair work also - not available for rent at WDW, but you could arrange for it (our son has his own).
We explained to the CM at Guest Services that for our son, stamina was an issue. The reality is, he just cannot pack it in like other kids, for medical reasons. When we explained this more fully, the GAC we were given fit our son's needs. Of course, this only applies when the family is moving together as a group.
This year, my son was not as able to enjoy the rides and my husband and his twin tried to enjoy some early time in the parks, used fastpasses whenever possible and were lucky to win dream fastpasses (this was at Disneyland). They used a few FP's and passed on the rest. Our disabled son was happy to pin trade, learn magic triack and show them off to CMs. I appreciate your son's developmental age doesn't allow this interaction, but think about what makes a day special for him and seek it out in the parks. When you see a smile on his face, you'll break out in one too.
You know, it's OK to allow yourself some frustration and time to feel a little sorry for yourself. It's natural to have these feelings. The challenge is picking yourself back up and finding ways to enjoy the vacation too. Do you and your husband share the feeding responsibilities? If you do, you can take turns blasting around the park with your twins. It will be your special time together. Maybe all the girls (you included) need to do some serious princess stuff together. I live in a house of boys (including my hubby) and I'd love this!
I have another idea for you for the future, but not sure how well it works as I don't know where you live. We tried Disneyland this year for something different and to experience the proximity of the parks, hotel etc. We had found the transportation at WDW to be efficient but daunting. It was also tough when our boys took turns getting sick and we did have to split up. At Disneyland, the parks (Disneyland and Disney's California Adventure, plus Downtown Disney) are smaller and SO close! We also stayed on property and found that we could split up and get back together easily, so we were never apart for long. It worked for us in all ways (excpet for jet lag...)
I hope you enjoy your vacation!