This was a major concern for us before our first trip to WDW with our son who has Aspergers too.

I think it will work to your favor that you are taking a long vacation and wont feel like you have to do a park open to close to fit everything in.

We think that taking breaks during the day has helped us to avoid any "meltdown's".

For us that means going back to the resort to get away from the crowds and noise for a bit.

But in 4 trips, we have never had to deal with a meltdown while we were at Disneyworld.

There is so much for them to focus on - including in the lines - that unless noise is a huge stresser, you will hopefully be surprised how easy your trip goes.

At Epcot, there are kidcot stations that offer a break from the crowds and they can do a craft.

Just finding a quiet place to sit and maybe have a snack for a few minutes can help.

I know that many Asperger kids, have a big problem with change in routine. I would suggest that you go over with him, what he should expect.

Our first trip, we made up a map for him with photo's of the shuttle that was taking us to the airport, a plane, a DME bus, picture of the resort we were staying at, pictures of the transportation we would get to go on, went over how you had to stand in big lines sometimes especially if the ride is really fun. For our son, the more he is prepared for what might happen, the less stress he has.