There should be trains available which make connections in D.C., from New Jersey, with less than a four-hour wait (#195 or #135 probably). Better still, you could avoid the layover altogether by catching your Florida train in NJ instead of Washington. Both the Silver Star and Silver Meteor originate in New York's Penn Station and make stops in Newark and Trenton on the way to Pennslyvania and points south. Really, you can connect at any station between NY and D.C.. There will be a difference in fare though, which means none of these suggestions work if price is the reason you are changing trains in Washington.