I have the room with floor for my 2500.
It has its own roof under the awning ,couple of vents on the truck side, three windows with roll up covers, and a door.
It also has a door on the truck side to access the interior of the truck. The bottom is heavy gauge pvc and seems to be all around pretty heavy duty.
Easy to attach to the awning. It slides into the channel on the truck side and clips to the horizontal and vertical tubes. Lots of stakes included.
I like it but have only used it out now twice. Great spot for the dog to sleep when he's gross.
Here it is in the driveway not stacked down.