Based on the discussion thus far, I have created 3 proposed itineraries, one each for the Roanoke, North Carolina, and Florida ideas. For all, for the sake of brevity I roughly made Washington, DC the northern limit of travel, knowing well that those living in the Northeast would board or detrain north of there.
Roanoke: Just one Amtrak round trip, to Roanoke on Saturday evening, and returning from there on Sunday.
North Carolina: This would be 3 days, Friday through Sunday. Full day of travel on the southbound Carolinian to Charlotte on Friday. Saturday would be used to ride CATS light rail & streetcar, and then the late afternoon Piedmont trip to Raleigh. Sunday, board northbound Silver Star in Raleigh to head home or to Washington or Richmond for connections.
Florida: Just as proposed by Bill, this would take 5 days (Friday through Tuesday). Board the southbound Silver Meteor on Friday. Arrive in Miami Saturday evening. Sunday would be used for MetroRail, MetroMover, MIA Mover, and Brightline. Since Brightline service begins later in the morning on weekends than it does during the week, I made a mid-afternoon round trip Miami to West Palm Beach and back, which leaves the morning for transit and still accomplishes the Brightline trip in daylight, between lunchtime and dinnertime. On Monday morning, board northbound Silver Meteor, and arrive at Northeast points on Tuesday.
Any more suggestions, or is this enough to choose from?