We also took the Autotrain twice. You have to drive to Lorton, Va and you need to get there by 3PM. The train leaves around 4:30 and gets to Fla around 8:30 AM. It's then about 45 min. to WDW. I would definitely recommend a sleeping compartment if you do Autotrain. This may be more $$ than air travel.
I'm also from NY and we have taken the Auto Train many times. We are also going to WDW around the same time. The airfare for that week is ridiculous averaging $700 - $800 per person roundtrip. For my family (4) that would be
$2,800 - $3,200 just to fly there then we'd have to rent a car.
The Auto Train is $1,929 (with
AAA discount) round trip for all of us and a van with sleepers both ways. Close to half the price of flying and renting a car.
The train leaves Lorton, VA at 4:00 pm and arrives in Sanford, FL at 9:30 am.
(It used to arrive at 8:30 but they recently added an hour to the arrival time. Most of the time it will get in earlier anyway).
Cars have to check-in at 3:00 pm, vans have to check in at 2:00 pm.
They serve you dinner and breakfast in the dinning car (if you get a sleeper).
They also have observation cars where they play a movie at night.
Most of your time on the train you are sleeping. The nice thing I like is getting to Florida at 8:00 in the morning. You have the whole day and your not tired from driving 11 or 12 hours.
They have a family sleeper that sleeps 4 (2 kids and 2 adults) or you can get 2 bedrooms (deluxe or rommettes).
I think your 2 sons would like it.