this is a remodel in what was once a garage converted to living space. soffit will be through a laundry room & bedroom. I won't know about unions or valves until i open up the wall.
It is about a 10~15ft run so there might be a union. And I might have to "T" off to get gas for the dryer in laundry room.
I don't predict the need for a valve anywhere along the soffit. One end is the attached garage where pipes come in from utility, the other end is the kitchen above the bedroom so the pipes will run in the soffit in the bedroom and then go up into the kitchen, where the valves will be.