There is a gun shop in the desert across the county border to the west. It's somewhere in the desert in Nye County, might be abandoned. Just meet there. If no one is home, conduct the sale.
Just purchased a HK off Nevada Shooters site. Performed BG check $25 and transfer fee $50. At Bear arm on Basic st in Henderson. Great shop will certainly be back to shop at a later time.
I believe DPS waives the $25 bgc fee for private party transfers - the way I see it, you should have only been charged the $50 transfer fee as the shop would not have their account charged $25 by DPS when they called in the 4473.