First place to look re. where water got in to our TT

During a pounding thunderstorm today, realized I had a pool of water about 9 inches across, 6 inches wide and maybe 1/16 inch deep on the bedroom side of the half-wall dividing the bedroom from the rest of the trailer...also some indication of water (very little) along the camp-side wall of the bedroom


Most likely culprit? A leak around a window, that kind of hid the source on a site that wasn't perfectly level? Infiltration through the outer front edge of the trailer?

I don't see any evidence of wicking from the roof down a wall.

Ideas?