Do a little research and pre-planning!
You need to figure out the mileages between your start and end points, decide how many miles each day you want to drive, and how much time you WANT to spend at the places you are going to, to get an idea of how much you can manage on your trip, and what you can fit in.
Start with an atlas or an online trip planner like MS Streets and Trips (or even Rand McNally's free online program is better than nothing). Plot things out day by day -- then you'll have an idea of what is possible even if you end up doing it differently when you're actually on your way.
See our RoadTrip Planning section (there's a link on the green banner menu bar at the top of this page). There's lots of great tips there for learning how to plan a trip.
Think about what your daily expenses will be for food, gas, lodging and spending money. All of these things can be easily planned (estimated).
You'll find that the planning is almost as much fun as the going -- even if you don't follow the plan later! Finally, don't worry about having to plan each and every little detail, or sticking to a plan once it is set -- approach it with the idea that things will work out no matter what -- be flexible -- and plan mostly on having a good time. You won't think about everything ahead of time and that's not a problem -- most anything can be dealt with "on the fly." It ain't rocket science. Bob