I use LBRS for my farming (I farm for Insane achievement; I haven't sold any boxes).
My loop involves jumping down as soon as you can to the bottom level next to the river of lava. I then pickpocket all of the orcs on my way towards the spiders. Once you get to the Ogres that are past the spiders, you can do the next few parts in whatever order you like, pretty much.
Once you're finished with everything up there, jump back down to the place you jumped down to the first time. Instead of going towards the spiders, though, you go towards the trolls. Loot all the trolls in that area, then head back up to the top level of LBRS, looting all the Orcs as you go. This will lead you right back to where you started, so jump down and do it all over again. All of their pockets will have magically been filled since you last stole from them =)
(Just FYI, I average 60-75 lockboxes an hour doing this. Based on his assumption that they will sell for 10-20g a piece, it would be somewhere between 600g-1500g an hour, although I don't think I could get more than 3-5g each on my server, Stormreaver)