Every time you begin a new drawing, you turn the grid on, set the global linetype scale to 3.0, and set layer 0 as your current layer, with red as the color. You can do this using a template drawing, but you could do it instead with the following script, stored in a text file called setup.scr. The fourth line of the script is blank.
grid on
ltscale 3.0
layer set 0 color red 0
The first line turns on the grid. The second line sets the global scale for linetypes. The third line sets the current layer to layer 0 and sets its default color to red. AutoCAD LT assumes that in a script you want to use the command line version of LAYER rather than the dialog box version. The result is equivalent to entering -layer on the command line. The fourth line is blank, ending LAYER.