Kristen, I think I've posted here before that I don't have a problem with taking the kids out of school, especially in the younger grades. I guess you could say that was one of the gifts that cancer brought me - realizing that life is short and if I want to go make memories with my family which requires them missing a bit of school, then so be it. (Last spring we even took what we called a "Ferris Bueller's Day Off" one day DH and I were off, and what a blast we had - I wouldn't have given up that day for anything).
Of course, we don't overdo it, and the kids miss hardly any school otherwise and are good students. Every teacher we've had has been supportive, and it seems every week or so my kids come home to tell me so and so went to Disney (during school) so I know we're not alone.
I talked to the principal about his views on it one day and he said he believes family time is important and understands that scheduling sometimes can be difficult (my DH's job was such that he couldn't take vacation time during the summer, on school vacation weeks or major holidays because they were the busiest times in his industry), but also that a lot can be learned on such a trip about time, money, geography, etc.
This year (3rd grade) I really didn't want to miss too much so we scheduled our October trip Wed -Mon, returning to school on Tuesday.
I know that people hold strong beliefs both ways, but that's how I feel. I sense we'll have to become more creative as time goes on, but also my DH doesn't have those restrictions anymore, so that will help. We also are finding that more and more we're enjoying the resorts as much as the parks, so even if we go at a busier time of year, it's not going to ruin our trip, we'll just build in less park time and/or adjust our expectations.
I know you're a teacher by profession. Out of my teacher friends, one would never do it, and another used two personal days when she cruised with us last year so I think she'd do it more if she could. Funny, I met a teacher in line at the airport last October -mind you it was a Monday night. She was with a group of 6 adults who'd gotten a house for the weekend, and I guess she'd used a personal day for Monday. She overheard me telling my kids they had "school tomorrow", so she chimed in "so do I", in fact she taught 3rd grade. Her friends were ragging her because they all wanted - begged her - to stay another night and she wouldn't. She really wanted to, but she couldn't. So I know that might play into your decision as well?