Remember that you might get a sprinkler installation man to do this one task
for you. Also, cable installers do this all the time. These two
industries have a special machine that would do this job in 15-20 minutes.
If you find a small (as in one man) company, they might to it for a very
small fee, especially if they frequently come to your neighborhood for other
Try to see who does sprinkers/ or cable installations in your
neighborhood. Many cable companies use independent contractors to install
cable tv wires, and I get the impression most of them are one man ventures.
Hope this helps.
The water pressure idea is also good, and is good advice if you wish to try
it yourself. It is a common method.