It's your turn to be service-y. I have three books I'm trying to track down based on hazy childhood memories, so I thought I'd open it up to your collective wisdom, and then you can tell me/us yours.
1. Okay. There are these two girls, they are friends, one is short and the other one is really tall, they decide to live with each other's families for a summer, obvi they figure out they like their own parents best, the short one is writing a terrible romance novel and the tall one tries to stunt her growth with coffee and chocolate and other things that don't work. OH, and the one writing the novel gets almost sucked in by one of those pay-to-publish scams and they want her to use a sexier pen name.
UPDATE: The Great Mom Swap, Betsy Hynes. Thanks, @Meritaten!
2. My notes for this part of the post say: "circle pin razor banana cream pie the Byrds" which is mostly it. There's a girl, she's in high school (maybe middle school?) and all the other girls have circle pins, and she's shaving with her dad's razor, and gets paired up with someone useless during home ec, and they make a disgusting banana cream pie, but then I think they eventually became friends? Oh, and she's really into the Byrds, as was I at the time, but I think she was into them like "here is this hip and current band I like," and I was "I don't go anywhere or do anything and just listen to my dad's LPs."
UPDATE: Fourteen and Holding, Candice Ransom. Thanks, @Miss Sparrow!
3. This one is NOT the one you are thinking of. It's a kid who gets sent back to Arthurian times during a field trip, or some such thing, and his mom is too, and she keeps waiting for the cream tea she was promised in the brochure. But there's a book people always say I must be thinking of, and it is NOT that book, which is not super helpful for you, but I really must know what it is.
Anything ringing bells here? Anything at all? And what are the lost books haunting the transom of YOUR mind?