To quickly move around the spreadsheet grid sheet try using
Ctrl + arrow keys
You will move the active cell in the direction of the arrow key you click.
In a table you will move to the far edge of the table as far as there are entries.
If the row or column is blank you may find yourself at the extreme edge of the spreadsheet grid.
Press the opposite direction arrow to move back.
Press Ctrl + Home to go to the top left of the screen if you need to.