
Perhaps the "1928 Manual for Courts-Martial" ?

maybe
One Good Tern Deserves Another? Published October '94, coming of age story, boy & girl characters, coastal setting, author in the middle of the alphabet...
Also, you might have missed my earlier suggestion above, since it looks like we posted at the same time. :)
Maniac Magee for the book that Heather suggested. (and I agree!)
Miriam - for the link to the book that Laurie mentioned.

Congratulations on finding your book, Bloom! I'll move this thread to "solved" and update the group bookshelves.
And here's the GR link:
Evidence of Things Unseen

Anastasia Krupnik would have been my next guess, too. I'm pretty sure she's a city girl. And spunky!

The Alice series by Phyllis Reynolds Naylor? I can't recall if she lived in NY, though.

Congrats on finding your book Camille. I'll move this to "solved" and update the group bookshelf for you.

Congrats on finding your book, Amber! Here's the GR link:
The Cobra Event

Yay! Congrats on being reunited with your lost book. Glad I could help :)

Well, I don't think I know this one, unfortunately. I'll poke around a bit more and see if anything comes up. In the meantime, I've changed this thread title to be more descriptive...that may help attract the attention of someone who recognizes your book. Let me know if I got it wrong.

There's also a teen surfer-girl series called Luna Bay, but I don't think it has a Massie in it.

I believe this series is The Clique: Summer Collection by Lisi Harrison. I think the first one is
Massie

Yay! I'm glad I could help. Now that I'm on my PC and can link, here it is:
Forget-Her-Nots

Possibly Forget-her-nots by Amy Brecount White?