I wrote via Scholastic UK and got a letter back from one of the publishing assistants along with a kind of BSC pack, which consisted of a pink BSC folder, The Babysitters Remember poster, a BSC badge, an extra copy of the postcard that came with the UK edition of Mary Anne's Makeover and a 1995 BSC stock order form. The order form leads me to believe that it was a promotional pack for bookshops, but I still think it was quite a cool thing to send to a fan.
My favorite writing-to-AMM anecdote was posted in the BSC LJ community -- someone wrote to her asking why the vegetarians in her books ate fish, or something, and she sent back a form letter with "Fish is not meat" written on it. Lord love her.
I wonder if I'm too old to write to her now. It would probably be kind of weird, right? OR... maybe she would be like "cool! a long time fan!, I better send some free stuff and use her name in a book.."
Oh, I got the mainstreet books from the library, but the maps were taped down. I hope they aren't important.
^ I have a closet full of that kind of stuff. ;D If it wasn't for my mom, my dad and I would be living under a mound of papers. I can imagine that AMM probably actually does like getting letters from fans. I would. ;D