how much progress was made by 1975 in implementing the agenda of the
1848 Seneca Falls Convention?

Click on the "Declaration of Sentiments" on this site:
http://americanhistory.about.com/library/weekly/aa040101a.htm

I would suggest that all of them have been met by now, and were mostly in 1975 -
the Roman Catholic Church excepted, but I expect that the ladies
didn't really expect that.  There is still the "glass ceiling" for
women's promotion in some fields, and certainly was in 1975, but in
the main, things have moved the way they wanted, probably a lot
further than they could even conceive.