Returning vet, what's the grind?

Level 300 player with several other accounts at least Level 50, been playing on and off since release. Haven't really played for about a year and a half. My built is pretty complete or a least it was until now, I have good 3 star weapons and armor and all the perk cards, legendary perks, and mutations i could need. But I know that legendary effects are craftable now and they finally added 4 stars! Plus burning springs and likely other things I haven't done. So what's the new high level grind? Events to look out for? Best legendaries and how to get them? Becoming a ghoul good or bad? New plans to search for? Maybe some explanation on legendary crafting?