User blog comment:Wikiwalker11291/Continuation of SAO - Beyond Alicization and Other Storylines/@comment-6697950-20160811040925

Honestly, I doubt whether Progressive will go on for that long unless Kawahara starts skipping, or at least skimming, through floors. Otherwise, closer milestones like the 10th or 25th floor are more viable points to end the story. I honestly don't think that grinding-obsessed Kirito without Asuna would be that interesting for a story on floors 30-49.

As for the other spin-offs, I highly doubt that any of them aside from Girls Ops will connect with the main series. So far, the Alternative series seem to be avoiding contact with the main series excluding minor references. Probably to make it easier to manage canon. Since Girls Ops is working with the same cast as the original series but with some extra characters, I could imagine the two crossing over, especially since Kawahara will be forced to write original stories from now on.

As for the game characters, I highly doubt that they'll be making any appearance at all. Maybe in the anime or mangas, but it sounds like too much trouble to do cameos for them in the novel without either retconning the story or rewriting the characters to fit into canon.

I'll refrain from commenting on Alicization as it's not yet fully translated. And on that topic, you might want to tag your spoilers before you get an angry mob with pitchforks and torches. Not everyone here has read the web novel or been spoiled on it and the title of your blog post doesn't include a spoiler warning.