I've driven from Windsor to Kissimmee 5 years in a row during March Break...love it. There are 5 of us so that's $2500-$3000 in airfare vs. under $500 in gas: I look at it as someone paying me $2000+ to drive and I do all the driving: 1400km day 1 on the way down, and all in one day on the way home (though I plan on 2 days). Also I stay off site so I love having my own vehicle down there.
That being said, I have been going for 10-14 days each year: if I had a week or less I don't think I'd drive: that's a lot of driving for 5 days or less of actual vacation time.
That directly relates to my comment about ability to fly from US airports.
We booked the flight for our XMas vacation on Frontier Air from Syracuse, NY (probably not a good choice for you) to Orlando, FL. The direct, return flight, leaving Dec18 and returning Jan08 (so outside actual XMas vacation and flying mid-week which makes it cheaper), is a total of $176USD for the 2 adults, 2 kids (i.e. $44USD each). But this is a very no frills flight with personal item only (i.e. backpack) - no checked luggage, no carry-on, no seat selection, no meal.