I tried reading the rails guide, but I would like something which assumes a little more experience on my part, and moves quickly in the deeper parts.

Try just in time rather than just in case learning about it, then. If you think railsguides are too easy, I won't suggest railstutorial.org, even though it's unfinished, it's excellent.

But yeah, maybe the best way for you to learn would be start a little project, and look up things as you go. Don't forget to use gems. There's no reason to write a test harness, there's cucumber. No reason to write user login systems, there's authlogic. The list goes on.