Funny you should mention Golden Earth Girl. When I'm doing things like this where I go through some unwieldy catalogue full of albums I'll probably never listen to again, I make a playlist with songs I think might be worth revisiting. That was my one and only pick from Off The Ground. Beautiful melody on the verses in that one.
Right now my feeling on solo Macca is that everything from 1970 to 1980 is at least decent, I can see myself revisiting every one of those records. After that you get a lot of forgettable stuff, but usually with a gem or two each time as you said.
I don't like Driving Rain very much but otherwise his run from Flaming Pie to the present is decent. I noticed the lyrics on his later stuff seem to get personal and introspective in a way they never really did before, which is interesting.
Press To Play was as horrible as advertised, absolutely shocking production on that one.
My vote for most under-rated McCartney album: London Town.