I've been going over this one for the past couple of days - first time trying to play it. First, I played along with it a couple of times, then listened while reading along with your chart. Finally figured out - I've been hearing it wrong all these years! I heard bars of 6/4 (or you could say extra bars of 2/4), but when I counted along with your chart discovered it works best just counting 4/4 the whole way through! I think it's because it goes back to the tonic early in several sections, and I always started feeling the beat starting over there, but you have to just count it as beats 3 & 4 instead of reverting to 1 & 2. I still can't play it right though!
I also think you are right about it going back to the A during the lead. And I thought your corrections were right, except I also think that there is an extra bar of A in the intro that shouldn't be there. (though that could also be related to the way they were playing it in '77 - I was listening to the original studio version) What an interesting song! I wonder if they had charts when they learned/recorded it?