Trip planning can be a daunting task. Going somewhere new can be both exciting and anxiety provoking, especially if your means of transportation is a bicycle. Issues such as altitude, road conditions, and availability of provisions are some of the things to consider when creating your plan. Another issue is route finding. Taking a wrong turn and going 10-20 miles out of your may not be too big a deal in a car, but it could have big consequences on a bike. There are many tools available to the bicycle traveller, but some level of planning and familiarizing yourself with the general geography can go a long way to ensuring success at finding your way. Some items I use for planning, ensuring I am on the desired route, and ideas for things/places to see include: guide books, gps device, map (paper and electronic), and recommendations by locals.
It isn't always necessary to plan every detail of your trip. You may want to leave some room for spontaneity and act on a tip from someone you meet on the trip. But knowing what choices you are making and how they relate to your overall plan is helpful.
When I am planning a trip to a general area but don't know all the specifics, I like to lay things out in Google Maps. It is very helpful because you can place waymarks on your route, color code them, make notes and place website links, note contact information, and place them on the exact location. This provides a visual map of places in relation to each other. It will tell you exactly how far apart things are and provide suggestions for how to get there.
I will be doing my first organized multi-day bike tour with Adventure Cycling Association this summer. This trip is already planned out, but it is in an area that I am unfamiliar with. I have made a sample planning map using the itinerary of this trip. You can see an example of what I described above by looking at my map here.
I use Google Maps quite a bit for directions, planning, discovering, learning, and just plain geeking out. I like that I can save my maps, share them, and refer to them later.
I am curious to know what other tools bicycle travelers use for trip planning and route finding.