Hello!
I will start by saying I didn’t have time to read all of the responses, so I will apologize if this is repetitive! I will also start with the fact that I’m an “anything is possible type person,” so that’s the attitude I enter this with. I think you could do it, and here are the tips I would offer.
1) Stay in a monorail or gondola resort (I did see this had been mentioned already). This will help a lot in managing equipment.
2) Figure out how to get yourself a power wheelchair (I also saw suggestions for getting this mentioned). The biggest thing with this is that you cannot rent one at WDW.
3) I think getting a
DAS should be possible for your family. I would enter by saying that your husband and all of your children have conditions that you believe would qualify you for this service. I would then give examples that include your preschooler’s tendency to have tics that could disrupt people verbally and physically, and your child’s difficulty with behavior and waiting in line due to her autism (I know they do not accept diagnoses, but this is language that I think many will be able to relate to.). If they need more than that, by all means be ready to explain more. I think that, since many people in your party have difficulties with waiting in line, this should be a reasonable accommodation for your group.
4) I do think a double stroller is your best option for the combination of kids you describe. You could look into options of double special needs strollers, but I’m not sure if they exist or not. If they do exist, you can bet WDW has them to rent somewhere.
5) Plan midday visits to the parks with late mornings and early evenings. Decide that 12-7pm or something is reasonable for you and then plan around it, sticking to those times. Select FP during those times, and if you do obtain a DAS, plan to use both together. Select a few attractions at each park you plan to visit and see what you can get done. Don’t set unreasonable expectations.
6) Consider if planning table service meals would help. They might be too hectic, but they might also offer respite from heat and stimulation. Disney is fantastic with dietary needs as long as you tell them what you need in advance.
7) Bring all the snacks and drinks you need to help your children with dietary needs.
8) to go with 7, place a grocery order to help have foods you need available.
9) Do any of your kids have a PCA that could travel with you? Bringing an extra adult who is familiar with the needs of even one child could be very helpful.
10) Cooling vest and fans work great for heat related issues!
I know I was thinking of more things, but I have forgotten them. I do think you could do this, but I think it would require a lot of planning and reasonable expectations.