I have not taken a train ride for 10 years, but it was way better than any plane ride I’ve ever been on. The worst seat on a train is better than the best seat on an airplane (or a bus, for that matter). And nothing compares with first class on a train.
Some things to consider –
You are probably looking at one of the Silver Service routes to Florida. These are Viewliners, Amtrak’s tackiest long distance trains, and coach on them is not as nice as coach on the better double-decker Superliner’s trains you find on routes out of Chicago and points west. Coach can get a little steamy. Look into first class accommodations. The roomette you described (3’6" x 6’8") is for two adults. You want one bigger for kids – a bedroom or a bedroom suite. When comparing prices, keep in mind that a first class room includes meals, and meals on a train are expensive.
Those NY to FL trains have an option with which you can have your own car loaded onto an auto carrier and take it with you. This might compare favorable with car rental.
Plan on being late and be pleasantly surprised if you are not. After all, if you were in a hurry, you should not have taken the train in the first place.
Dining on the train is a hoot. They’ll seat you with anybody they can to fill a table, and you meet interesting folks. (Best diner partners – A couple from Australia who asked “Are these grits?” “No, ma’am, those are hash browns. You don’t want grits.”) Food on a train is excellent if you have a real dining car. Club care fare is usually frozen sandwiches.
The bar in the club car does close, but they’ll sell you enough beer to last through the night.
It is more comfortable to sleep in a booth in a closed club car than in your coach seat.
Very interesting things happen in the smoking lounge. We had quite a party on the Chicago to DC overnight run – an open bar, thanks to a liquor salesman with samples, and even a dancer.
How old are the kids. Take the Gameboy, the portable DVD player and some books for them. They won’t be anywhere as interested in looking out the window as you are. You will enjoy looking out the window.
Check any big or valuable luggage, but have some bags with what you’ll need for the day and a half you are on the train. Bring snacks – as I said, the food is expensive.
I once took the train from Kansas to Florida and back, and I was able to enjoy several different routes – Southwest Chief from Kansas to Chicago, Capitol Limited from Chicago to DC, Silver Star down to Orlando, then returning on the Sunset Limited from Orlando to New Orleans; City of New Orleans from NO to Chicago, and finally, the Southwest Chief back to Kansas. All in all, an excellent experience, especially when I was able to to get first class. It is very relaxing, and I highly recommend it, although NY to FL is not the best route.
And forget about the bus. The only people who take the bus in the U.S. arfe those who are either too poor or too crazy to have a car, and there are way too many of the latter on the bus.