Haven't played anything other than the story since Lahai-Roi, best way to max out asterites before 3.5?

Hey Guys,

Not exactly a returnee, but I have mostly focused on the story since Lahai-Roi and haven't had much time to get into the events or much of exploration, also haven't started 3.4 yet. I have about 10.5k asterites and 830 afterglow corals right now.

I want to save up as much as possible for 3.5 and thinking about farming asterites these few weekends, what would be the best way to go about it?

Also, is there a way to get lucy without spending asterites? Only from ingame rewards?