I've never heard of Peak.
My Fleetwood (I've heard the stories too but mine has been really good.) says "aluminum frame" right on the outside. Well, the roof trusses are wood, the area around the door is wood. The framing around the front window is wood.
I was in a campground one day when a guy stopped by to admire my camper. He said he used to work for Fleetwood. I asked him about the framing. He told me roughly where the aluminum was and wasn't. Basically, the vertical walls that were full height were wood. Anything curved, or shorter than full height was wood.