You said the dog sleeps in the house with the guys. Where in the house?
She probably needs a solid half an hour of "just her" time in a day. She needs to be reasured that she is loved, and gets played with, and attention. Especially still being young.
I have a Min Pin, and got him when he was 5 months. He barked for 3 days in the house, and since, has been totally cured. We would interrupt him by talking loudly and firmly to him. He understood that we meant business. The water gun is a simple $1.99 tool that will help "interrupt" the barking. It is totally harmless, and can be used along with firmly saying "no/quite/shhh", etc. He now is only allowed to bark outside, or at strangers. I do not think that it is "cruel" to try to stop a dog from barking, however, it is not necessary for a dog to bark at every sound and movement. Healthy, normal, completely content dogs will very rarely bark in the average day. They have no reason to bark if they are completely content. Packs of wolves and coyotes dont sit around barking and yelping all day, just when they are herding, calling eachother, hunting, etc.
Your corgi will need a bit of undivided attention for a while. Like you said, taking her home and spending time with her will definately help. The clicker may help in interrupting her barking, and then putting her attention on you. It should work well. Another trainer is Ceaser Millan. He has a television show called The Dog Whisperer[/i,] and works with all types of dogs from badly aggressive pit bulls, to insanely abused and mistreated chiuaiua's (sp). He does not use sound at all, just firm movement, and state of mind. He works with dogs, like they would work with eachother in a pack. He is AWESOME!