Haven't done NYC to WDW, but I've done Pennsylvania to WDW and DC to WDW as well as DC to NYC and CT. And some mid-west states to WDW, but that doesn't really apply here. Basically you hop on 95 south and drive until you hit Daytona Beach then take 4. It isn't a terrible drive. Except when you pass through cities at rush hour- that is never fun. You'll hit Philly, Baltimore, DC, Richmond at the very least. Depending on how long you want to take you can stop in DC for a day or two. That's only a couple hours outside of NYC. We always stop at South of the Border. It's a kitschy Mexican themed rest stop in South Carolina. Some people don't like it, but it's a family tradition for us. Stop, restroom break, get ice cream, fill up the car, then keep on going. I think there's an arcade and restaurant there, too. Plus there's signs counting down how many miles are left until you get there and that's always fun. There's also Savannah, GA, which has some very pretty parts.
There's some websites that can help plan a road trip, too. We used Furkot when we were planning our move from DC to Louisiana. Roadtrippers looks more user friendly when it comes to finding interesting things to do on the road.
Editing to add: Some roads have tolls. 95 in Jersey does. I think I bypassed PA when I was going home from CT so I didn't pay any tolls there, but PA does have toll roads. So that's something to remember, too.
