"A book lying idle on a shelf is wasted ammunition. Like money, books must be kept in constant circulation. Lend and borrow to the maximum--of both books and money! But especially books, for books represent infinitely more than money."
I forgot to say, there's a map on LFL site (that I personally find hard to use) so you can look up LFLs in an area where you might be heading. I did use it successfully when I took books with me on a trip in December. I didn't know any good release spots in that area so looked up LFLs ahead of time in a few towns I knew I'd be visiting and was able to find and release in several of them.