I do most of UBRS first and then drop down to LBRS normally just going straight to bosses and nailing any mobs I can't walk past. The important bit is to make sure you kill all the spiders in LBRS and get the Iron Spider Silk (or whatever it's called) as you can make better tailoring items to DE and get the Greater Eternal Essences (can go for up to 20g on my server).
With all the green/blue drops to DE, runecloth and rugged leather to make things for DE plus pots, recipes and trash drops then 400g is definately achievable. If you cleared absolutely everything everywhere in both UBRS and LBRS then I would imagine you would make a lot more but I've never done a complete clear.
I run with 5 elemental shammies and literally steam through the mobs. I've Leroy'd about a third of the Father Flame room just to see what would happen and the shammies survived which I found fun. Even Drakki is very easy which I guess isn't that surprising. Have been thinking about trying ZG just to see what that's like but haven't had the time recently. If I get time later in the week I'll report back.