Hello my friend from a different world! Same name here as there, so I'm sure you'll know me!

Scuba is here somewhere, too.
The layout is slightly different. He may go around a corner expecting to see a certain thing and it won't be there. Restaurants are different and found in different places. Bathrooms are in different places. The way you sit on rides can be different.....some places they're side by side and some places they are one behind the other. Winnie the Pooh is back in Critter Country, not in Fantasyland. The monorail is simply a ride, not a main way of transportation. Rides that are in completely different parks are together in
Disneyland (like Star Tours). There are more "wet zones", especially in Bugs Land. It's very easy to get soaked, especially if your son is a seeker. I just bring a change of clothes, as I know we'll use it. Or, with my boys, I dressed them in swim trunks and t-shirts. Swim trunks always dried faster. And I brought flip flops/sandals for playing in the water, but socks and shoes for the rest of the time. I'm not sure what kind of electrical parade they have at WDW any longer, but they do offer the original Disney's Electrical Parade at DCA. I'd definitely make it a point to go to Aladin, too. Way cool. Not sure if they have that at WDW, we haven't been there for years, and when we were, we didn't do MGM. I'd be cautious of playhouse disney, honestly. Everyone sits on the ground, and unless you're right up front it's hard to see, and lots and lots of people around. My DS is now 13 and has outgrown (or become more accustomed to) many of his sensitivities, but he would have had a tough time in that one. Lots of shrieking kids and no personal space. I did this with just DD and she told me she didn't want to do it again. You may have a different experience, but I thought I'd put it out there.
I personally think the walkways at DLR are a bit smaller and lead to more congestion. Important to know if you have a runner. Oddly enough, my second one, who isn't autistic, was my runner, and Zoe is so confident that she just assumes everyone is following her!
PM me your address, if you're comfortable, and I'll send you the maps. Also, if you take a look at the maps online, I'd be happy to go take whatever pictures you'd like and email them. (I'm always up for a Disney trip, it's even better if we have a reason to go!)
I personally really like Hojo's. They are able (and very very willing!) to make whatever accomodations that they can. Their rooms are larger than most. I like the view. You can watch fireworks from there very easily. Might work well, if everyone else is ready to head out and DS doesn't want to leave because of the fireworks.