Soft and Gooey

Oh yes. The faux-wood-look vinyl covered a bit of floor rot. The entire floor is bouncy and the right side is not secure.

Being under the trailer myself, I am better understanding what I've seen in photos of other trailers. Below is my photo taken from the ground looking up into the area normally covered by the belly pan - the underside of the plywood floor. The step should securely attach to the frame here. The step on the right is photographed from the rear of the trailer and looking forward. The 3" deep (aka tall) C-channel frame shown on the left.

Below: As expected there is floor rot at the typical 1950's segmented C Channel. The first photo shows the C-Channel flat on the floor.

The photo below shows a small strip aluminum - remaining when the rest of the belly pan was cut off and removed. This aluminum belly pan strip was pulled down through the rotted floor to below the chasis frame. On the right side of the photo is the segmented C channel.