If your school system is truly going to count Disney as educational (ours DOES NOT and I don't feel it should) then I would think whatever you could drum up would work, and it wouldn't really matter as long as it sounded vaugely connected to something. At this age they are doing sequential counting by 1's, 2's, 5's ect, and phonics skills to name a couple of areas. Come up with something he can count and something he can sound out or read.
I teach Kindergarten and when I have parents going to disney, I suggest a making a disney ABC scrapbook (bound on notecards at an office supply store or an all out photobook on Shutterfly or something), and journaling something they did each day. If you want to add education things to it, you could add in map reading. 5 is young, but they still like to know where they are, where they're going and how to get there. I guess I think they're remember more about a family vacation than they will what they learned the 1 week in school.
PS - I'm pulling my 3rd and kindergarten boys out for a trip in Jan - just booked our airline tickets
Our district does allow them to take family trips and be excused. The first year I had a letter typed up with what they woud be learning at each park and Principal Kindt said to skip it in the future. They already had about 100 differnt versions of the same thing from the internet or from peoples brains and alrady knew what it would say. 
It really depends on your district rules and the such.
When I said that I was speaking to a family vacation, not taknig classes at Disney. The two are very different. I am aware ofthe YES program, and our school district says that half of your time must be spent on structured educational activites such as YES for the trip to count. That would be a completely different trip from a typical family vacation at disney. A typicaly family vacation at Disney just does not have enough "educational content" for me to personally feel it is justified as an educational trip. My school board happens to agree with me on this. Others seem to think that it is educational enough. I don't see it beyond possibly 1st to 2nd grade. The YES programs offer the type of educational experience that would justify it for an older student, but a parent would have to work pretty hard to do that on thier own, and in our district would have to provide some serious documentation.State Regulations- School Attendance
Commonwealth of Pennsylvaniaregulations permit educational trips or tours sponsered by persons or groups other then school agencies. Provisions of the regulations provide that students may be excused from school attendance for an educational trip or tour upon reciept of written requestfrom the parents of the students involved.
Only have this because we are submitting our form today
To address the *shouldn't be excused as educational* part. Disney offers several organized educational activites. My kids are participating in the YES program. Its approved as an educaional resource for homeschooling. Not being contentious, but maybe you are not aware of such offerings? I only learned about it here, and I booked for our October trip last week. Our school is very heavy on the early science learning and my kids have discussed simple and complex machinery, special effects, robotics, centrifical force, ect. as we wait in lines. Everyday learning can be fun and just as important so kids can seethe principals of what they have learned applied around them
