Are you sure everything is going okay at school? I would talk to the teacher to make sure that things are going well for him socially and academically. I think there is probably more to the this than meets the eye. Good luck.
I'm pretty sure things are going OK at school. It's less than 2 weeks in. His school does multiage classses so he's a 4th grader in the same 3/4 class with the same teacher he was with last year. I got an email from his teacher (in response to my email about taking the trip) saying he was really stepping up and being a leader with the 3rd graders. He's not a stellar student, but definitely meeting all grade level expectations, and scores "proficient" on all measures.
The issue with him wanting to please, at the expense of expressing his own issues is part of who he is -- when he was 6 months old his daycare teacher told me she noticed that he never cried when the toddlers took his toys, just went on to something else. When he was in preschool I'd go pick him up from a playdate and the other mom would say "I'm so glad to find another child who is obsessed with dinosaurs", when in reality he wasn't in to dinosaurs but knew that playing with them would make the other child happy. Sometimes it's a great attribute -- he's consistently kind, gentle, follows directions because he wants to make people happy, and sometimes it breaks my heart because I KNOW that he's not taking care of himself the way he should.
I should say that when I say that we need to get away and reconnect, it's not that anything awful is happening in our relationship -- but I've been working long hours (10+ hours a day), and he's also at an age where he's off doing his own thing much more (sports practice, playing in his room, sleepovers with friends) and I just feel like we need some time together. Also, some of the ways we connected in the past aren't really working -- e.g. I used to spend hours reading to him, now he's moving into reading to himself, I used to take him to Six Flags (we have season passes) and ride the ride with him, now he wants to invite a friend and they leave me on the bench while the ride some ride that would make me motion sick.
Oh, and luckily we have some time to figure this out -- the penalty for changing now is the same as the penalty for changing 6 days before the trip, so I'm not going to actually cancel until the last minute. We're planning on driving so there's no plane tickets to cancel. One thing he and I talked about is either going and spending most of the days on day trips to the beach. Another is making it a shorter trip to a nicer place (e.g. trading those 7 nights at All stars for a couple of nights at the Beach Club), and saving the vacation days for maybe a short winter ski trip.