I bush-hogged around the cabin, especially where the two private electrical poles are going to go. That took most of an hour, and required a break. I was running sweat even in the chilly morning. Then I bush-hogged the area above the undercroft wall, where the rest of the house is going to go. After that, I cut down one big dead tree and a lot of little weed trees. I was shaken, bruised, and cut by thorny vines by this time.
I loaded up the bush hog and returned to town to check it back in. The guys in the yard asked me how I did with it. "Imagine that you have a rhinoceros that thinks it's a beagle," I replied. "And while you're walking it on a leash, it sees a rabbit dash into a thicket."
I grabbed some lunch and returned to the holler. It was time to do some persnickety positioning of posts where the concrete piers are going to go. I did my best to line up the corners, then did a measurement of the hypoteneuse from corner to corner. I was within a half inch or so of dead on. Good enough. I also made a rough estimate of elevation with a string level. The three back piers (high side) need to be about 16", 18", and 23" to match the undercroft wall height.
Next trip, I'll get out my laser level and do some even finickier leveling, then dig out the areas for the concrete forms.

Backside of glory
Building site from the back fence, looking down on the undercroft.