I've worked for 9 hours in May so far.
Act 3 is trimmed, spell- and grammar-checked, and copied and pasted into the master "final" file.
I made myself an outline of Act 4:
19 story chunks in 10 chapters (some chapters near the end are very short).
Of the 19:
14 need relatively minor editing
5 need more extensive editing
Not too awful. I'm already through the first chunk. 18 to go!