These "Return to:" achievements are not exactly going away. If you don't do them while they are current, they just rotate down into the side story category to be completed whenever. It hardly seems worth quitting, or taking a large break from the game over. It is in your best interest to do it now if you struggle at JPs, while there are mesmers around to help rather than say in 3 months when the map will be fairly dead again and mesmer assistance will be much more fleeting.
It took me hours to complete the first time. After that I have happily accepted mesmer assistance to skip a couple of the really obnoxious jumps. I'm mediocre at JPs at best. All told I think without mesmer assistance you need to do it four or five times to get the legendaries. First three of those without grabbing the chest because of mursaat coin locations which are required to start the Aurora collection, which are in unrecoverable locations without some kind of necro ghost walk or mesmer portal to get back on track. Then once again for the Aurora collection, and now for the Amulet. There are other ways to get a Legendary Amulet though if you really can't stand it.
Whatever path you choose, its an optional achievement, if you don't like it, skip it! Don't let it ruin your game. Good luck.