Having picked up about 2,000+ characters from Chinese, one of the fastest ways for me to acquire a feel for Japanese grammar and word order, as well as some useful kanji readings, has been to study classical Chinese texts in kanbun. Yet I constantly struggle with the resources available to me. I know that there have been some multi-volume collections of kanbun which ought to be in the public domain, like the 漢文叢書. But I can't seem to find a good online resource. Ideally, I'd like to be able to pick any classical Chinese text and study a kanbun reading of said text.
There are many public domain books available online at the Diet library, including a bunch of kanbun: http://kindai.ndl.go.jp/index.html
Your chances of finding a free online resource will generally be lower as the work you're interested in gets more obscure. (Conversely, if you're going to be reading Confucius or something I think you'd be much better off just spending 500 yen for a paperback edition -- 岩波文庫 or 講談社学術文庫 or whatever.)
As Zhen Lin says, though, kanbun is not really a good way to get a good sense for Japanese grammar and word order, or vocabulary... The minimal reordering into SOV (compared to SVO) and so on is present, it's true, but in general kanbun has a very idiosyncratic style that differs in many respects from standard modern Japanese. (Edit: But, let me state for the record so as not to sound negative, I think that reading this kind of work can be very rewarding, and it can certainly help with understanding "pure Japanese" works that are nevertheless strongly influenced by kanbun -- which covers a lot of territory up through, say, WWII).