This second one is definitely YA. It's called "Beware That Girl" by Teresa Totten. It's about two girls-Kate and Olivia. Kate comes from a working class family and her parents are not in the picture. She has worked the system to get a scholarship at a very exclusive school with the idea that she will eventually end up at Yale. She works very hard, both at school and after school (she lives in a room behind a Chinese grocery and works there part time). Olivia is a girl from a very wealthy family. Her mother died when she was small and there was a stepmother, who is no longer in the picture. Her dad is a high powered executive and so her supervision comes from the housekeeper. Olivia is repeating her senior year because of a medical issue the previous year, so all her friends have moved on, so Olivia and Kate are both forced to make new friends, and find each other. It turns out they each have something the other needs-Olivia has financial security and Kate has mental stability and focus. I loved how the two dance around each other, trying to figure out their relationship and what happens when boys/men come into the picture. This was a very fast paced read and I liked it a lot.
This last one is more middle grade again. It's called "The Lost Cipher" by Michael Oeschle. It's about a boy named Lucas who's father recently died in Afghanistan. His mother left when Lucas was a baby so he lives with his grandparents. His grandparents decide to send him to a camp for kids who have lost parents for a week, which Lucas is not looking forward to. For one thing, he doesn't think he really needs any help. For another reason, his grandparents are looking to sell their mountain property to a developer. When Lucas gets to camp, he finds that there is a bit of a mystery. There are stories of a treasure buried on the mountain and there is a secret code to find the treasure. Lucas would like to find the treasure so his grandparents won't have to sell the mountain. There is also a very rich boy who is a bully who gets on Lucas' nerves immediately and two new friends that rally to Lucas' side. Lucas and his two new friends decide to leave the group so they can go in search of the treasure. It's a fun adventure book. It would go well with books like "Hatchet" by Gary Paulsen or even "Escape from Mr. Lemoncello's Library" by Chris Grabenstein.