Is there a 'proper' way to do this or should I just append the table name to the 'url' option?

As a general point it surprises me that there aren't any generic examples for displaying the contents of any table you select, all the information would be available, column headers would just be the table column names, number of columns would simply be all columns.  One could thus have a generic jqGrid() call that would display all columns of whatever table name you put into the parameter which selects the table.