First off, congrats on getting ready to ttc. I hope everything goes well and quickly for you.
I completely understand not wanting to get obsessed about fertility, etc. I tend to become very driven and one-tracked minded myself. Hmm, in fact, I am right now!
Anyway, with that said, I would highly recommend Taking Charge of Your Fertility
by Toni Weschler. It will give you a very in depth understanding of how your body works, while still being a very easy read. If you don't want to go for the whole charting thing, I can understand. Although it is pretty easy to do, it can tend to focus you, especially if you are starting to obsess anyway.
What you can do, and one of the things the book explains how to do, is to take shortcuts with the charting method that still lets you easily pinpoint your fertile period.
I know I won't do it justice, but it basically means taking the couple of weeks after your period, and marking your temperatures and checking your cervical fluid. When you have egg-white cervical mucus, you are most fertile and probably about to ovulate. That only happens a couple of times a month, so it isn't much to obsess over.
Anyway, I hope this helped, and wasn't too long-winded. Best of luck!