Went on a x-country trip with my folks when I was about 13. It was quite a bit of fun. Saw lots of beautiful landscapes, a few national parks, and met lots of interesting people. The only place I wish he had driven through faster (i.e. ignored) was our stop in southern utah. It wasn't very pleasant, the folks there weren't very tolerant of visitors, and less so of visitors from a different cultural background. Our trip went from SF, California to New Haven, CT, and took approx 8 days.
I have but not all at the same time. But I have driven from where we live in west Texas to Florida, then from TX to California and Oregon on another occasion, and also up to South Dakota on a different vacation.
Just got back from a trip to Boston from Alabama. We also have toured the west by car, and on one trip, went from Alabama to several western national parks and the Santa Monica boardwalk.
Most times it was when I was a military brat. Dad was stationed in California. Dad's folks lived in New Hampshire, and Mom's folks lived in Alabama. Vacations were he**! Then my husband was military too! So I have most definitely traveled cross country! :D
In 2005, after my dad died in Florida, my husband and I loaded up the car my dad had left me with stuff from his condo and drove back home to upstate NY with only 2 very short stops for the restroom and a bite to eat along the way. It was memorable - lol! - and I'm happy I can finally say I've driven cross-country!
It's a lot more fun with a GPS unit so you don't have to stick right with a planned route. If you see something interesting that takes you off the path, the GPS makes it easier to find your way back.
Also drove from Regina, Saskatchewa to Tiajuana, Mexico.
Over the years, I have driven through every state in the union except Alaska, Montana, Wyoming.
I have also driven around Northern Mexico, and around Ontario, Quebec, New Brunswick and Nova Scotia, Canada.
(of course .. some times this was while in the Military and PCSing .. with CHILDREN (shudder!))
Now as a Retiree whose children were all grown at the time (and out of the home) .. THAT was fun!)
South to North, I-5, I-15, I-65, I-81, I-95. Never go near DC/ Baltimore during rush hour!