On a recent driving trip I made from my home in Virginia north up to Erie, Pennsylvania; and then west to Cheyenne, Wyoming, I used route plans which I'd gotten off the web.
If you look at a road atlas of the U.S., it's easy to see the major highways that crisscross the entire country, and so it's easy to figure out which highway you're going to take to you destination.
But, what about getting on and off those highways? What happens when you're driving on a five-lane divided highway outside the anthill that is the Baltimore/Washington DC nexus? Is that highway going to continue on, as it seems to say in the atlas, or are you going to have to exit off the highway you're on, onto a spur, and then zoom onto the continuation of the highway.
Travelling along at 70 miles per hour, keeping your eyes on those overhead signs that are supposed to tell you where to go, can be nerve-wracking.
They are slightly less nerve-wracking if you've gotten directions from the computer, because those directions tell you exactly where your turn-offs are going to be, and how long you drive before you'll be able to get back on the highway.
Of course, they have a caveat, as they themselves will tell you. Put in your starting point and your endpoint, and you'll be given the quickest way to get somewhere, not necessarily the most scenic. And of course, their might be a time lag in between the time highway construction is started, and it is reflected in any directions you receive. So you do have to be aware of that.
The driving directions let me down only once. I was in some small town in Ohio, I can't even remember the name of it anymore, but I pulled up directions from my motel to Cleveland, and wrote them carefully down. Yet the next day when I tried to follow the directions, the road I was supposed to get on petered out at a dead end, and the roads to left and right gave me no clue of which way to go. I had to go into a gas station and get directions.
But for 99% of the time, these directions worked great.
I didn't want to have to hold a paper in front of me while I was driving, so I wired a clipboard to the top of my steering wheel (cutting off all but the top inch). By placing my carefully folded directions on the right edge of the clipboard, I was able to see all my guages, including that all important one telling me how fast I was going, and I was able to safely drop my eyes down to look at my next exit, then look back up and carry on my way. The poor woman's GPS.
Several sites offer driving directions, including http://maps.yahoo.com and http://www.mapquest.com/. I'd suggest inputting your details into each system, and comparing their routes.