I think it depends when in the school year and for how long the trip will be. Generally, I think anything more than a week is excessive.
Meet the teacher ASAP and get lesson plans ahead and plan ahead! Find out if any testing will be held while your chld could be away or shortly after returning.
I would not want to remove my child later in the school year when testing and evaluations are heavy and very important (not only for my child, but for the school!) Testing scores in my area affect how much funding they will get in the NEXT year!
I give his teacher every consideration of time to give us lesson plans ahead of time. I either make him do them ahead of vacation or during. He would rather not do them during vacation, so he does the extra effort. I did have him keep a journal of our trip, so he is working on his writing, spelling, etc. I have him keep a bank book to keep track of spending, so he practices math.
This year, Epcot is going to be a little of a science trip!
You might even ask a teacher if their child can write a report on the trip?
Yes, I think the younger children are, the easier it is to pull them out, but I also think that the lower grades are foundation years. THis is when young students develop a work ethic in dedication to their schoolwork and social structure!
Good luck
Lisa