Having traveled across the country and back twice now, I thought I'd offer some advice on the topic.
To paraphrase The Hitchhiker's Guide to the Galaxy, the US is big. Really, really big. You have no idea just how mind-bogglingly big it is. Until you attempt to drive across it, that is.
Two ways to do it: completely scheduled or open-ended. Open-ended (no schedule, just going where and when the winds take you) is ideal, but reserved for retirees or independently wealthy. For the rest of us, you need to plan a schedule. Three to four weeks is ideal, but taking that much time off from work (not to mention being away from home for that length of time) isn't always an option. Two weeks is the minimum, but you can do a lot in two weeks if you plan well.
Thanks to the advances in the Internet over the last thirteen years, planning this trip was much easier than the first one in the summer of 2000. The first thing we did was took a map of the US and plotted all of the places we wanted to go. Then we did a preliminary route and realized that some things had to go. And through each iteration, a couple of places eventually went back in.
We used Google Maps to plot just how far we wanted to drive each day. You can plot a route and then drag it around to plot your distance, which is a huge time-saver.
Allow more time for places that are further away or are harder to revisit. We spent our longest time in Yellowstone, but only alotred a few hours for sight-seeing in St. Louis. Much easier for us to return there.
Know where time zones are! Plan them into your schedule. This is the number one thing that tripped us up. Also, realize that some states, like Arizona (and even parts of states like Illinois) don't practice Daylight Savings Time. Believe me, it's much better to know this ahead of time, particularly when driving West to East.
Realize, too, that there are a LOT of tolls on the East Coast and upper Midwest. After spending $60 in tolls on a trip to NYC a few years ago, we finally got an EZ-Pass, even though it wasn't available in NC. Smartest thing we ever did. Saved us a lot of time (not having to wait in toll lines) and headaches ever since.
With the route firmly in place, we researched each location and booked all of our hotel stays. We learned a valuable lesson on the 2000 trip when we didn't book a hotel between San Francisco and LA, thinking it would be fun to leave one night up to chance. Biggest mistake we made. We got as far as Santa Barbra that night, which didn't believe in billboards. So, we had to drive from exit to exit looking for a hotel. There's a long story that follows here, but that would require a whole 'nother post. Obviously, that's not a problem now that we have smart phones, but you're really better off having a specific goal for each day of driving. Gives you a real sense of accomplishment and allows you to relax more. Much less to worry about.
Try not to put too many long days back to back, which can wear you down. Sometimes this is unavoidable, particularly through the states in Mountain Time.
Be sure to plan short days, too, where you can drive a few hours in the morning, then spend the afternoon sight-seeing. This helps charge the batteries for the next day. You can also drive, stop somewhere for a few hours, and then drive some more before stopping for the night. Breaking up the pattern is also a big help.
Be sure to allow some time for flexibility. Some days, if you have a long drive, you may not have much choice. But you may see a billboard or something you didn't expect, or hadn't realized you'd be nearby a certain location. Side detours can be a lot of fun and a nice break, even if you only stop for ten minutes. That's what we did for the Jackson's house in Gary, Indiana, and it was one of our more memorable stops.
Don't plan too much, though. You'll have to prioritize and occasionally pass on something. That happened to us on our very first full day when we went to Cleveland. The Rock 'n Roll Hall of Fame was on the schedule, but low on the priority list. When we realized we couldn't fit everything in, something had to go. You just can't do everything. Likewise, check to see what everyone's priority is and use that as your guideline.
Two-three weeks is a lot of time to spend together non-stop, 24/7, much of it in one vehicle. Believe me, that's a LOT of togetherness. Have plenty of entertainment for kids: books, movies, and video games. One of the best things we did on the 2000 trip was get an outlet adapter for the cigarette lighter. That let us bring the Nintendo 64 (top of the line then) for the kids to play in the car. Madison hunted it down and brought the old 64 again for old time's sake.
Research the places you're going. While its fun to explore and discover, realize that you can't do everything on a whim (there will still be plenty left to discover). Some things need to be scheduled in advance, like tours (Alcatraz), shows (Beatles Love in Vegas), dinners (Bar-D Chuckwagon in Durango). We missed out on Alcatraz in 2000 because of this, and it was top on my priority list. We were only in SF for two days, but Alcatraz was booked a week out. It was years before I finally got to go. If it's important to you, see if you can book it.
Same goes for dinner. You don't have to book a fancy meal for every night, but if there's specific places you want to eat, book them ahead of time. This is something we always tell people going to Walt Disney World. If you just want to eat hamburgers, then don't worry about it. But if you want to eat somewhere nice, then you've got to plan ahead.
Chances are, you might need to do some laundry. We've found that we can travel two weeks without doing laundry (which required buying a lot more socks and underwear). If you do need to do laundry, try to plan that into your schedule, too. We did it twice on our 2000 trip: first at a laundromat in Wyoming, and second at Disneyland, which was much better.
When you pack, allow for a range in temperatures. Even in the summer, take a jacket and long pants. It can still get chilly up in the northernmost states, especially if there's a storm. We had temperature ranges from 55 to 120 degrees this trip. Those jackets really came in handy in Yellowstone. On our 2000 trip, we had to buy sweat pants for Madison in San Francisco. In July.
When stopping just about every night, you'll need systems. We have a specific method for packing car, and everyone has their assigned suitcases to carry. This makes things much easier when you pull up to a hotel that only has valet parking. Surprisingly, we never once used a bellhop on our whole trip, not even in Vegas.
Try to vary your fast-food intake, or at least mix it up. Good time to try places you've never been, especially when you're on the opposite side of the country. It's a challenge to eat healthy or not over-eat. We would grab fruit from hotel continental breakfasts. We also ate a lot of McDonalds apple slices, sometimes for lunch between a big breakfast and big dinner.
This is a no-brainer, but make sure your car is tuned up, tires checked, etc. We drove over 6000 miles in two weeks. Anything you can do to avoid a breakdown out in the middle of nowhere. Likewise, go ahead and stop for gas once you get down below a half. That was another mistake we almost made. There are places out West where you literally have to drive a hundred miles or more between gas stations.
Don't count on having cell service wherever you go, either. We were amazed at how little we had it, even on major highways. I can now name at least a couple of dozen places that the Verizon guy ("Can you hear me now?") hasn't visited.
And speaking of food and gas, be prepared to spend a lot on both. You can skimp on food costs, which we ended up doing to our surprise, but you're stuck on gas. No getting around that one.
And finally, be sure to carry an atlas. Don't just rely on your GPS. Sometimes, it won't always take you on the best route. For some reason, ours likes to find little detours even though we have it set to stick to major highways. Which is how we lost a lot of valuable time getting stuck in Belle Fourche, SD, when we should have just stayed on I-90. It's really best to get an idea of the big picture, have an idea of your surroundings, and know where you're going. Which is what it's really all about, isn't it?
