I personally don't need much in the way of planning. Even if I'm riding in an unfamiliar area, just keeping track of the cardinal directions via the position of the sun* and, if available, the most basic landmarks (a river, highway, mountain, etc.) is enough for me.

But if that's not your way, then I suggest studying routes on mapmyride.com and ridewithgps.com. You can even print out cue sheets from these and take them with you.

* A few years ago I was in Australia for a time, and i really had no clue about the local geography. I didn't mind- I was able to figure out how to get home for the most part. BUT, when I first arrived, I could not get it through my head that the sun was in the NORTH at noon. That really screwed me up.