Trace Adkins lost his Brentwood, Tennessee mansion to fire over the weekend, but his family is safe and sound, thanks to an escape plan they learned about in school.   Investigators believe the fire Saturday afternoon originated on a workbench inside the family's attached, three car garage according to  News Channel 5 reports.   An overheated power strip supplying electricity to a small "can-style" light is about the only source Trace' wife, Rhonda, can pinpoint.   But that is purely speculation so far.   "That's the only thing I can think of," Rhonda told reporters yesterday outside what remains of the family's two-and-a-half story home on Millsford Court.     Trace  had been on his way to Alaska for a few shows and fishing when he turned around and flew right back home.   Rhonda says they lost her "jewelry" room, Trace' s Harley Davidson and tons of other things, but his Civil War era weaponry was untouched.   Rhonda says this is a good reminder of the importance of having, and rehearsing, a fire escape safety plan: a concept that Rhonda says saved the lives of her two youngest daughters, the children's nanny, and a neighbor girl.  Read more here.      http://www.youtube.com/watch?v=k9H0Txpvijo