Charlotte, NC to Catholic University of America buses and trains from $31

Here are some trips other travelers have found on Routefriend.
$31
7h 40m
1 stop
Amtrak Megabus
$48
12h 40m
1 stop
Amtrak Megabus
$62
12h 0m
1 stop
Amtrak GotoBus
$66
12h 40m
2 stops
Amtrak Megabus
$80
8h 7m
0 stops
Amtrak
$96
19h 55m
2 stops
Amtrak Megabus