This is what I did to prepare my kids for missed school days. I wrote a letter to each teacher stating we would be going to "Orlando" and do some educational stuff such as visit Kennedy Space Center, Several Animal Sancutary's and some of the Disney parks too.
I also asked each teacher to please give all tests and assignments that would be due during our trip BEFORE we leave. I let them know we would be very busy and the kids would not have much time to do homework, but they would be writing a journal on a daily basis on the events that have taken place so far.
All the teachers went for it and we're cleared to go. By the way my kids have had a perfect attendance record for the past few years, that may have helped.