Pace yourself on that post hole digging. Sit down, don't fall down. LOL.
I've found a "bucket seat" for a 5 gallon pale is a good investment.
You can put in 4 or 5 empty quart yougurt containers to act as cup holders for your
water bottles and coffee, with a couple misc spots for other project stuff.
I've seen people make a round piece of plywood on youtube. I have a couple of plastic ones.
Great lifting plan btw.