I decided to try this again, painting from a photo and incorporating what I had worked out in my field study. Wow, this is the kinda thing I've read about!
I also wanted to see if I could simplify some of the bigger shapes, like the trees, so that not everything had the same jarring brushstrokes that the field study had.
Well, what took two and half hours outside, took only 1 hr today. I don't think it's really any better, nor any worse. I'm also having a very hard time mixing the right greens, for the lightest parts of the vines. Some highlights are yellow, but some are a very pale, yet warm, green. I think I need to use a different blue to make that shade. That means adding to my limited palette. Oh, well.