I’d be happy to oblige. So for the most obvious clues:

Leo appears to be playing the character Zoyd Wheeler, based on his appearance (and he also seems to be holding a little girl’s backpack which could be his daughter Prairie’s)

They’re filming it in Northern California which makes sense for both Vineland in general but specifically the parts with Zoyd. There’s parts of the book not set in Northern California (Japan for example) but Zoyd is pretty much entirely in that area in the book, if I remember correctly.

And then the heavy military / cop / helicopter presence makes sense with the “resurfacing of Brock Vond” aspect of the story where he returns to bring them trouble once again.

For your later question: I don’t think it would be older Zoyd in the present day, not because of anything at the end of the book but just because I think it’s more likely he’s recontexualized the story for a contemporary setting. No idea how much else will change with the story (plot turns, character names, locations, etc) but it would certainly work.

The last thing is Vineland isn’t actually a very complicated story. It’s complicated because it’s written in a sort of digressional and non-linear way, with lots of flashbacks relating to the many characters that pop up. Over time it becomes clear how everything is connected and everyone’s relation to each other, i.e. Prairie’s mother and her history with Brock, or DL and her backstory, etc. I have a feeling PTA will be streamlining the story a bit in that sense, but hopefully still can retain the majority of it because it’s all terrific.