It's under the window, on the passenger side .It goes from the pantry(it was a closet once) to the hatch.You're lucky, I think your 20FQ is aluminum framed. Our trailer might be the last year of wood framed Creeksides. Once 50 years ago I watched a prototype class C being built.We were still building the addition. The main structural wood was the inside 1/4" paneling, so on a stick and tin, you peel the aluminum and work from the outside. But here the interior paneling is only 1/8 ", so I doubt it provides much strength.