What your doing very much sounds like my plan if I ever get kicked out of my house for an extended period of time or something. . .
My suggestion is to become good friends with the librarians, especially since you're a very frequent visitor. I was suspended from school for a little over two months and during this time I went to the library 3 or 4 days a week, so the librarians began to recognize me. If you're extra nice and polite to them, it'll go a long way I'm sure.
Also, I think getting a job would greatly benefit you. It'll eat up some of your time so you won't be wandering aimlessly. Plus, even at minimum wage, think of all the things you could afford, especially foodwise! Buy a few loaves of bread and some Peanut butter and you're so for a while.
Just make sure you're nice to everybody who helps you in any way because they're helping you out of the goodness of their heart and you should appreciate everything you get.
I'd also suggest you invest in a notebook and pencil, I'm sure you could get down a bunch of cool drawings or stories or something!