I done the drive from NJ to FL alone many, many times! Flying is not an option for me, as I get violently sick on planes. I usually take the AutoTrain in one direction (a five hour drive from my house) and drive the other (a 20 hour drive since I drive the speed limit!), but it is still about 25 total hours of driving! Over the last six years, I driven 19 times, either Florida to NJ or NJ to Florida. And I did these trips in an older car - as of this January, I was driving a 11 year old car with almost 200,000 miles on it, even! But it was reliable and I felt it could make those trips, and it did.
I am cautious about things when driving alone, such as I am very picky about the hotels I stay at on I-95, as I will only stay in "better" brands that have interior corridors (usually Hampton Inns or Fairfields), and I am willing to pay for it. I am also picky about where I get gas, as I look for well-lit, well populated towns off I-95.
Before I discovered Disney, I actually went 8 years without a vacation, mainly because I had no one to go with, and I wasn't willing to go by myself. I finally got over that, and realized if I always try to wait for others to join me, I would still be waiting, going nowhere every year! So I do the drive alone, and just use common sense and hope for the best!
