Are you really sure that it's going to cost an extra $600?
We just did the break-out for my in-laws who would be coming down from the Annapolis area. We figured it would take 2 days driving each way with 3 kids, but that they would not need dinners the last 2 nights:
Here's what we figured:
2 nights hotel: $100 per night ($200)
Meals for 3 days x 5 people: breakfast, free with room, lunch at fast food, $30 ($120), dinners slow food, $50 ($100) snacks, etc... purchased before leaving $100 - TOTAL=$320
Gas for SUV: 1800 miles total, using approx. IRS rate of 32 cents per mile to figure gas/oil/wear & tear: about $550. Even just figuring the gas, it would be about $300.
By the time we added it all up, it was going to be close to $1000 to drive.
They got 5 tickets for $135 r/t on SW from BWI-MCO, will be there in less than 4 hours door to door, and the total was $675. They got a car rental for the week for $125.
Once we did all the calculations, it was a no-brainer!