Old player returning, what to do?
Do all the JPs Find all the diving goggles and perform the perfect dive.
Kill all the bosses from the related achievement tab (good luck with Hydra Queen -_-).
Try your luck at WvW.
Try getting transformed by the skritt burglar. Find and complete all the mini-open-world-dungeons. Become a Master Chef.
(Seriously though, since I don’t do PvP and don’t know what else you enjoy, it’s difficult to make recommendations)
Polka will never die
Join the ranks of us alt-o-holics and make a new character. And another and another and…
One of us! One of us! MWAHAHAHAHA XD
Anet gave us the Living World while you were gone. Basically new content release every couple weeks to keep things fresh.