Halfway there. 400' to go. Excavator now has 45 hours on it. I probably spent 10 of those grubbing, and my first 10 hours trenching were not all that efficient, but now it kind of looks like I know what I am doing. After the boulder field, I hit this monster that was the size of the mini ex. I thought about getting an impact hammer attachment, or going up the street and offering the guys running a full size excavator on a nearby job a few hundred $$ to pluck it out, but decided doing a slight "S" curve around it made the most sense. Mercifully, as soon as I passed it, the soil changed from a really hard packed material to a much softer sandy loam that was really easy to dig. It would be interesting to have a geologist on site during the trenching, but I'm guessing the end of the boulder field corresponded with some underlying geological change.
I now see why most long term equipment operators have bad knees. The constant jumping in and out of the machine, and jumping into the trench to check depth really beats you up. Some type of laser range finder attached to the bucket would be awesome.
Ironically the agency that has been the absolute most difficult to work with on access and power easements (USFS) has these markers that are perfect depth gauges. The top of the first yellow sign is exactly 60".