The first of the two stories I got, The Wrong Chalet School, is a fun story for fans of the series, but there's nothing particularly outstanding about it. A girl with an extremely absent-minded aunt is accidentally sent to the Chalet School and various lightly amusing things occur. There's actually more about tennis than about the main character. The second story is set much earlier in the Chalet School chronology and while it's kind of blah on its own, it tells the reader how Jo Bettany originally became an author and teacher at the Chalet School. It also introduced the character of Polly Heriot.
For those who like their school stories on the fluffier side (Chalet School, by the way, has an underlying thread of religious faith), I also found a copy of Pamela Cox's continuation of Enid Blyton's popular St. Clare's school stories. Enid Blyton's school stories are everything the Chalet School isn't - in fact, almost every Chalet School story contains a warning against such trashy reading, pretty obviously directed at Enid Blyton, which I find hilarious. Pamela Cox does an excellent job of capturing Blyton's racy style and plentiful slang and tricks, while removing most of the outdated racism.
In case you're wondering what the difference is....Blyton's characters are definite anglophiles. French girls (and teachers) don't understand the English concept of "honor" and tend to be sly and lazy. American girls are vulgar and stupid. The Chalet School is an international school; the first pupils are French, German, and English. The second owner and Head of the school is French, and while American girls tend to be presented as having a more undisciplined upbringing, they're just ordinary girls. St. Clare's girls use slang freely, often to the teachers. Chalet School girls are fined for using slang. St. Clare's girls are constantly playing tricks. Chalet School girls certainly get into their share of mischief, but school pranks are considered childish and the kind of silly thing they do in ridiculous school books - obviously a jab at Blyton.
But I enjoy reading both, light fun reading if you're into series and like school stories.