Not fully understanding what you are looking for here. You seem to be on the right track on how to select down, and thus I would presume pretty good at navigating excel via the keyboard, so these are just variations on that:
If you are creating a formula and you are selecting upwards, you can do what you were doing already, but with a different direction: CTRL + SHIFT + UP ARROW.
If you have some blank cells in the column you're working with, keep holding the CTRL + SHIFT portion, and tap the up arrow.
If you have a lot of blanks and know you want to head straight to the top* of the worksheet, press CTRL + SHIFT + HOME (takes you to A1*), then while holding SHIFT, use your arrow key to move the selection back to the single column you started from.
*Takes you to A1 if you don't have any frozen panes (View > Freeze Panes)