I don't have answers for most of your questiongs, because we 1st--we co sleep with our kiddies, and we are still working on the training wheels (my son just turned 8 and has problem with keeping up with two wheels) But for the books--that's easy--get a spacific bag for books. And/or a spacific shelf for your books and use that one spot. At our library we can check out book bags, so we use those. Sure, the books do end up getting taken out. And when it comes to returning the books, keep the list of books and two days BEFORE they are due, put them all together. That way, if you can't find one, you can look longer and not panic. Where I'm from, we get reminders from the library 3 days before due, and they have a website to go to to see what you have checked out and you can re-check things out online. You should see if they have that at your library. (soooo useful!)
Now, for plus size pants, I have experience--me being fluffy and all(and not wealthy)--I find that pants that narrow in as it goes down the leg works better for me--check out the stretching jeans, that works. And, if you are not sure what your size on, go to a plus size store and start trying them all on. That's what I did. Go the fashion bug, if there is one (the one in our area has recently closed) And if you need to get pants, find a plus size store and see when they are having a sale. Stores always have sale. You just have to take a look around. And if your lucky to be to size that walmart carries, go that way too.
Hope this helps some!