While I haven't taken almost a week off from school for Disney I have for swim meets. I have also taken a few days off for Disney, but usually only 2 or 3 at the most.
Your work load is going to be coming from where you get your notes from. Online? Friends? etc... You need to figure that out first.
Are you in classes that take attendance or in lectures where it doesn't matter so much. If your professor cares about attendance, I would tell your professors now that you'll be on the trip so you can be prepared and so they understand. Some professors are not going to like it and you could get in trouble, while others won't care as long as you show up for the tests. By telling the ones who could care now you might be able to work around any class requirements the week you're gone. Also, the truth of the matter is you could get attendance or participation points taken away from you if those things matter (usually in sections or smaller classes). Again, if you talk to them now, they might be will to help you out though.
When I took trips during school, I studied in cars, airplanes, in hotels, etc... I spent 2 days of school at Disney World (for the Princess Half Marathon) and actually missed closer to 3 days due to traveling and what not. In the airport, hotel room, and lobby I was on my computer studying and taking notes. Most of my studying at the park was when I was waiting for my friends to get there or when I was waiting for the Magical Express to take me to the airport. I still had a lot of fun though as well.
In short, talk to any professors that might have an issue with you being gone. They might not care or they might make your life a bit difficult, but it's better to come clean about it. Finally, study and do work while there, but don't forget to have a magical time!
