Thanks for all the replies. I did something this week that I recommend every parent do at some point: I went to the school and spied. The kindergarten playground is right out front, so I was able to park, nose in, and sit there like I was at a drive-in movie with a broken speaker, watching the action but unable to hear what anyone was saying. It was tremendously educational!
DH spied on her one day, too. Rode by during his bike ride and the kids happened to be out. So he hid behind a tree (probably looked like Chester the Potential Molester--I told him I hoped he didn't wear his trench coat) and watched while DD played ball with a boy classmate.
We discovered that DD was far from ALONE on that playground. Both days, she spent a few minutes by herself, obviously comfortable being a horse or singing a song. She played with a group of girls she'd been chatting with at the snack table, she played on the structure with another group of kids, she bounced a ball with the nice boy she's made friends with, she hung out at the drinking fountain with Park Girl. Best of all, she did not appear to even be interested in joining Neighbor Girl's soccer group (where there appeared to be a bit of strife--one girl appeared to be being sent away, shoulders hunched, by NG while NG held hands with a third girl). DD talked to her teachers a bit--obviously telling them some story, complete with animated hand motions that seemed to make them smile. She obviously is comfortable talking to them, with approaching her classmates, with playing by herself, with being approached by her classmates. She was friendly with NG--sat next to her at the snack table--but was not at all joined with her at the hip. This is exactly the scene I hope to see continue. We want to be friendly, but not too close, with these neighbors. Honestly, as I watched those 32 kids, I only saw two groups that concerned me: NG's soccer threesome, and a large group of roughhousing boys who got reprimanded by the teachers for what appeared to be ganging up on a smaller boy. Otherwise, all the kids just seemed to be fluidly changing activities and playmates, alternately hooking up with each other, ignoring each other, wandering around alone. Most of them were by no means sophisticated.
My own DD is very inexperienced with the playground scene, and I think that has colored her view of things somewhat. She's come home absolutely horrified by some of the behavior she has seen. She didn't attend preschool, and her playmates and playdates have been pretty strictly ruled by DH and me. So for her to see kids telling others they can't play, or pushing each other, or cutting in line, or tattling . . . well, these are behaviors that she's never been in much of a position to deal with, until now. And, believe me, I'm not sorry she's inexperienced. (For a highly sensitive kid like her, being 5 and dealing with this stuff is far better than being 3 or 4 and dealing with it.) But it does mean that we may be talking a lot more about playground social issues than other parents who had those talks when these kids were in preschool.
Fianna, I'm glad you replied--I think I remember from posts earlier this summer that your daughter's in a similar situation, coming into kindergarten without much in the way of preschool. I'm glad she's doing well!
And lab, yeah, I'm thinking I need to BUY a copy of Odd Girl Out if we're going to continue living next door to NG. (When I read it this summer, it was a library book.) I hate to pigeonhole a 5-year-old and hang a label on her, but the behavior I'm continuing to see makes me believe that we're best off staying a bit aloof.