I'm so glad you asked. And since you are in MD. I can offer even another alternative. Take the Amtrak AutoTrain. We do this every trip. You take your own vehicle, pack it up with
everything you need or want, and drive to Lorton VA, which is about 5 minutes south of DC on 95.
Then they load your vehicle onto the train while you check-in and board the train. There is no waiting in line to get through security. You just have to have an official ID with photo. You must get a sleeper room... coach doesn't cut-it. The train departs around 3:30 to 4:00 pm. As you're waiting to depart and for a little while after they have a Virginia-wine and cheese tasting in the lounge car.
At check-in you choose your dinner time of 5, 7, or 9 pm. and at dinner time you are called to go to the dining car and have a very good, cooked to order meal, that includes tea, sodas, wine, etc. and a delicious desert all served on real china. Typically, they have Prime rib or NY strip, Salmon, Chicken, Vege only, pork. You don't get to choose sides, but it surprises you how good a train meal can be. This is all included in the ticket price (sleeper).
They show a movie at 7 pm and again at 9 pm in the lounge car. We're early to bed early to rise so we typically choose the 5 pm dinner and watch the 7 pm movie, then head to bed around 9 pm. You will find people playing cards, using their laptops, watching DVDs in the lounge car sometimes pretty late. The car is usually full during the movies though.
Sleeping on the train takes some getting used to, so one's first experiences are usually fragmented sleep at best. The train only makes one stop in Florence NC to change crew (usually around 1 am).
They have breakfast (continental) starting at 6 am in the morning (cereal, begals, muffins, fruit, etc). The train arrives (if on schedule) at around 8:30 am in Sanford (aka Orlando). It typically takes 30 - 60 minutes for you to get your vehicle off the train. Then you drive your vehicle to either WDW or VB. I personally would do VB last for the relaxation time.
Now. When you look up the costs you might gasp a bit, but you have to take many things into consideration. You have to deduct the airfare, cost to rent a vehicle, no driving service, no parking fee at your departure airport, you can purchase and carry your own beach chairs, umbrella, and boogie boards and bring them home to use next year. You can pack and carry cheaper (non perishable) groceries purchased at your home supermarket. And the non tangibles... you're driving your own vehicle, you don't have a carry-on limit or have to deal with dreadfully long security check-in lines, ticket lines, waiting for luggage, lost luggage, and I'm sure I'm missing something else, but you get the point.
It' not all sugar plums and rainbows, but for us... it sure beats the heck out of flying.
Sorry, didn't mean to hi-jack the thread.