[Shodo]

You can do it alone, it's just risky and consumables are just about necessary (since the swirlspines can root).

I had a druid with me just to show me the way, but if you're comfortable navigating the zone this would be the solo method:

-Get enduring breath (grab a fishgill extract from a potion vendor if you don't have an EB item)
-Head to Phinigel's room. Start swimming in toward the guardians, then use a Shiny Brass Idol to get invulnerability (or use your own Divine Aura spell if you're 54).
-Swim straight for the ground spawn - you only have 18 seconds, so make sure you're confident of the location beforehand. Either figure it out on the map or find a youtube video or something.
-After you pick up the ground spawn, use a Leatherfoot Raider Skullcap to teleport out to WC.
-Done. Idol + Cap recharge = ~850p to finish your quest.

If you want to go in extra ballsy and cheap, leave off the idol and hope you can dispel root/use lay on hands to survive long enough.