Just found this guide - very nice.
"... to complete every single quest in the same run, a task which would make even the most hardcore of players groan." We didn't groan, we just went afk to get more coffee
Two weekends ago I was in a party of guildies that cleared everything except the Four Horsemen, Ice King, Unwanted Guests and New Souls (yeah, two easy ones but we wanted to take on the Four Horsemen for kicks and we were tired so go out with a bang). We did clear out many of the beasties though.
No secret doors here either, no Gwen. What we cleared in the UW took us about 7 hours, if anyone's wondering about time span. That's including PC breaks and a good amount of goofing around 'cuz we were there to have fun. everyone gained about 5 plat, many gold items and 5 skill points. Only five or six Ectos dropped total I think.
Definitely worth it, but I'd like to reccomend three monks, two with rebirth and one with Unyeilding Aura to get a fallen member up right away in combat because it gets rough. The enchantment gets shattered in many places but there are more than enough areas in which it can be a life saver. Also three monks just in case one of them disconnects or is forced to leave. Finishing off the Chaos Plains (clearning monument, not doing 4 Horsemen), it got pretty hairy and my monk just sat up by the Twin Serpent Reaper waiting to rezone. The spider was giving me the creeps after a while.
Ah - almost forgot - no Terror Shields dropped, which was our initial reason for going and clearing out the Spawning Pools. They didn't drop there or anywhere in the whole UW for that matter. And that was a lot of Terrorweb Dryders since we didn't leave any alive.
Looking forward to a FoW-clearing guide and comparing notes on it, we took that on in another approximately-12-hour marathon coffee-drinking session this past weekend.