That really depends on where you live. I can drive a hour in almost any direction and not be out of town. So for me it would be 2.
Are you thinking opening a range?
I care more about who I'm shooting with than where I'm shooting. I think other than the once or twice a year type of thing that it would have to be within about 2 hours to make it a regular thing. I drive about 1.5-2 hours to meet up with folks in Houston but that is pretty close to the maximum for me on a regular basis.