Brenda takes a long time to fall asleep, and dreams of trying to slay a dragon with a checklist as her first piece of high school classwork but she's lost in the high school which looks like the public library but huge and she isn't wearing pants. When she wakes up she assumes that the whole thing with Alpina was more of the same until she opens the cover and to check and there it all is, list of absurd powers and conversation about the true nature of reality and everything.
She has a long debate with herself about whether to bring Alpina to school or leave her at home. Eventually she decides on the latter, because if Alpina's going to disappear or turn back into a blank notebook she'll do that from anywhere, whereas "Brenda gets caught writing in Alpina and there are awkward questions" can only happen at school. She explains the risk to Alpina before breakfast and hides her deep in a desk drawer even though her parents haven't snooped in her room for years, and spends the entire school day thinking about tonight. She goes to the hunting and fishing store and spends the last several years of accumulated allowance on all the camping gear from her list plus a sleeping bag and a big backpacking-across-Europe style backpack to carry it all, and stashes it in the garage in the pile of miscellaneous crap where nobody will realize it's new.
She writes a letter for her parents, explaining the whole truth, because once she's gone they won't be able to stop her. Maybe they'll be angry at her if when she comes back but at least they won't have been lied to in the meantime.
She sleeps again, with an alarm set for well before her parents will be awake, and puts on her sturdiest clothes and her big soft jacket and the backpack with all her camping gear and food and books, and sets the camcorder her mom used to make home movies with recording on top of the letter on top of her desk, and smiles at it as she tells Alpina,
Alright, I'm ready. Let's go!
[Final build: https://no-vices-for-you-to-exploit.netlify.app/#BAEEFAIGDA4SFBgaHB4gIiQmKiwuMDI0CwYICh4iJCowQkRGAwgKFA==]