AbstractTableWidget is fairly easy to get started with, because it binds NetworkTables variables to your objects of type StringTableField, NumberTableField, BooleanTableField or BooleanTableCheckBox. You don't need to write any NetworkTables code. The sending data and receiving data happens automatically if there is a change.
I found it helpful to look at how the PIDEditor was implemented in SmartDashboard.
I made a few extensions that extended PIDEditor. You can see them here:
http://forums.usfirst.org/showthread.php?t=20437