As a tip I have been giving away to friends and family lately (since I live so far from them), there are 2 other forms of transportation that I am aware of for long road trips that do not involve flying (expensive) and driving yourself (tiring).
First, consider taking the train! Amtrak is a system that provides transportation to many major U.S. cities at about half of the cost of flying. See the sights, or just relax while you travel. Traveling by train, I have looked, typically takes about as much time as it would if you were driving yourself. The delays come from making stops along the route.
Secondly, there is also megabus.com. Megabus provides a bus system with extremely cheap fares ($5-30), however, there are some limitations here. A) It only goes to MAJOR U.S. cities. So if you don't live close to a major metropolitan area, this could be a problem. B) Since you are going by bus, can take much longer than it would than driving yourself or by the Amtrak system. If time is of the essence, this might not be the best option.
If you are taking an upcoming trip, or would like to but do not have the money to fly and/or can't drive, there are some other options out there. If any readers have some additional travel shortcuts, send them my way or post them in the comment section!