January would be a less then ideal time of the year to drive down. You never know what kind of weather will be thrown at you. I've been hit on long drives with bad weather causing bumper to bumper traffic on the highway due to accidents.
January also means you don't get the luxury of all the nice rest stops along the way. I actually find most of the rest stops to be really pretty and peaceful being secluded in a forested area. Nice for a picnic.
So if you picked a less wintery time of the year to go i'd definitely recommend these rest stops over McDonalds.
I've made the trek a couple of times out of Ottawa to both Myrtle Beach and Orlando which takes approximately 18 hours and 25 hours when driven straight through. And I do drive it straight through.
I've got young children and I find driving through the night to be quite beneficial because they have no problem sleeping in the car and it means less time hearing them fighting

. Its also obviously quite a bit quicker rather then stopping overnight.
Halfway through we stopped at a Chuck E Cheese. This was a fun/good idea as it broke up the drive somewhat without really slowing us down too much.
As much as i'm an advocate of night driving I happen to be a night owl so drowsiness isn't an issue. I'm also really good at napping in the car so when my wife is driving i'm getting an adquate ammount of rest. If you are one to nod off while driving then this might not be a good idea for you.
Also the savings are absolutely crazy by driving down. Especially with the current really low gas prices. I think i priced it out from ottawa to Orlando and it wasn't even $400. I'm a family of 5. Imagine how much it would cost to fly us all down there. Add to that the fact that we don't have to rent a car while down there.
The drive, while long, isn't actually that bad. It becomes part of the trip. I'd recommend downloading an audio book to listen to in the car. Personally i'm a horror fan so the World War Z audio book is really super produced with famous actors doing alot of the voice work (way better then the movie).
Finally by driving down you also cut out alot of the hasstle of an airport. I've had horrible experiences of multiple flight delays and a full day being cut out of our trip due to errors on Deltas end. This way you have no stress about making connecting flights or arriving at an airport hours before your flight.
Theres no doubt that if flight prices were lower i'd be flying. I'm just saying that with the savings you will be having it really isn't that terrible to drive down. Just think maybe about finding a warmer time to go

.