Terra Arcane wrote:

Just curious if you know a better way to dig a 50 foot long 6-inch deep
4-inch wide trench on a steep slope along the driveway in rocky soil?

It's to bury a remote gate opener sensor wire (12 volt).

I'm guessing my options a
1. Shovel (back breaking)
2. Gas-powered ditch digger machine (might not handle the slope?)
3. Pressure washer (slow)
? and other ideas ?

Depending on how rocky the soil is, one of the tracked vibratory cable
plow units might work well. One advantage of the cable plow is that you
don't need to backfill after. Tracked units can handle operating on a
pretty steep slope, and the vibratory plow works ok in rocky soil if the
rocks are small enough that it can push them to the side.