I found this handy schedule in a Volos newsblog. Some may find it useful, since the ANES ferry line website is unfortunately spectacularly difficult and therefore unhelpful to those who want to move on with their lives. (They might do a little better with their “presence” on creepy,creepy Facebook, but I’ll never know).
The Mantoudi route with the mighty Proteus ferry is still the most efficient Athens connection in terms of travel time, especially from Glossa. The free ANES connecting bus from Skopelos to/from Glossa is a great idea.
There is the occasional Mirtidiotissa ferry to Ag. Konstantinos (arriving at night) but once passengers traveling to Athens without car get to Ag. Konstantinos they are own their own. Choices are either a late night taxi or hoping for a KTEL bus from Ag. Konstantinos to the city.
Flying Dolphin Erato returns to the fray 22 May.
Things will improve as the summer approaches.