I agree book, about the kitchen for sure. Actually just the concept of space is one that has always been important for us. We have primarily stayed off site in a timeshare villa because it gives DS a chance to feel like he is at home and for him that allows relaxation and decompression.
My biggest tip after having an undiagnosed child for a long time but dealing with the issues nonetheless, is to take it slow. We tried pushing DS to hurry from one thing to another and quickly realized that did NOT work. We might think, "Excellent! No line!" but he would rather have the time to warm up to the idea of a new ride while waiting in a bit of a line.
At all costs we avoid anything 3D. NOt only do you have the whole visual issue but they are LOUD and random thigns happen unexpectedly.
I also bring ear muff kind of things to let him wear when he needs to--WDW tends to be VERY loud on all rides and attractions. We take a break when he needs to, which generally means he and I sit on a bench and watch people go by and chat while DH takes the other two on rides.
My other biggie is water. One thing DS struggles with with his SPD is figuring out when he is thirsty. Or hungry for that matter. My mantra is "when in doubt give him a drink and a snack." Sounds nutty but if he is hungry or thristy he is all out of whack and his tolerance plummets. That is easy to overlook on vacation when you are on the go. He is actually a little underweight for his height so this has not led us to any problems.