bob wrote:
I need some ethernet cables between my computer room and the TV room.
The easiest way is to run the cable in the crawlspace and then up
through the floor for about 1 foot.

The plan is to drill a hole from the crawlspace up into the space
between two inside walls (one of them is the TV room) and between two
studs. Then I can make an opening on the wall for the faceplate and
the network jack. There is an electrical outlet on that wall, but I
don't think that's going to help.

If I could drill the hole from the top between the walls and between
studs, that would be easy. But since I can't get a drill inside the
walls, I have to drill up from the crawlspace. How do you identy the
area between two drywall, from the crawlspace looking up?

Use the wire for the electrical outlet as a reference. It goes into the stud
space you want.

Or, cut the box hole and drill from there down using a flex bit. Do some
research - there is a special tool to flex the bit a little extra so it comes
out in the middle of the stud space rather than perhaps too far to the far side,
although maybe this doesn't matter on inside walls. The flex bit has a hole in
it to pull through a string to pull the wire.