Coming from Westchester County you'll probably want to take the TZ to the NYS Thruway, take that south to I-287 in NJ. Follow that to the NJ Turnpike south. Go over the Deleware Memorial Bridge and follow 95. Take the Harbor Tunnel through Baltimore, gte onto 295 south (the B-W-E) and follow to 95. We like to get on 95 in Greenbelt, others will tell you to take 295 through DC.
Follow south over the Wilson bridge (look to your right for a nice view of the Capital and Memorial as you cross). Stay on 95 to Rishmond, unless you are driving in the middle of the night, take the Richmond bypass--295.
Again, stay on 95 south until you get to Daytona--then get onto I-4. Daytona is about the 1.5 hour mark to WDW. Not much right off the Interstate though. Your best best is to keep driving to Altamonte Springs were there are a variety of hotels, the Hilton is nice and has decent rates. There's also an Embassy Suites and some more budget oriented places. Depending on teh time of day you think you'll be arriving, there's a Macaroni Grill about a mile off I-4 not far from both of those hotels.
If you're willing to stretch to about the 2.5 to 3 hour mark, there's some decent looking budget type places in the St. Augustine area.
Anne