I think your referring to a Roadtrek camper van.
If so it's considered a class B. As to how quiet, Road trek is a premium builder, they are known for quality products, but remember you are looking at a very small space. An AC unit or even a refrigerator may seem quiet in a house, but if you sat two feet from it, it may seem very loud. Inside a camper this size, you are sitting within 3 to 4 feet of basically everything. If an appliance has moving parts, you will likely hear them.
Also the windows on this are no different than those in an automobile, sounds from outside will be heard inside much more so than in a house with thermopane windows and 4-6 inch thick insulated walls.