Anyhow, made some progress. Walkway deck is in, and 3 of the 4 outer support boards are in on the main deck. I have to pull one pole out about an inch and a half to have a shot at things being square. Oh, speaking of square, I'm reasonably satisfied with the 26 foot walkway. Its about a 1/2 inch out of square over those 26 feet. A professional should have done better, but not too bad for an amateur. Built a bit of scaffolding to help. Looks like I'm going to end up with a spare pair of 2x12x20' boards - I think of something to do with those on the next project (a combination chicken house and kids fort).
If the rain holds off a day, I should get the decking on the main deck and perhaps the handrails up. Then all that is left is trimming the 6x6 post even, and painting all the decking with some sand filled pant (to make it less slippery). Once the main deck is done, it won't matter if the pond fills, I'll be done with all the below future water level steps.