Measure HxWxL carefully. One thing, if in a slideout, the floor of the slide may ride up and over your actual floor, so using any replacement sofa, the seat height may be higher (due to the false floor that the sofa sits on) and you can wind up with your feet dangling off the floor. Inch and a half makes a lot of difference on seat height.
Bill, Kathi and Zorro; '05 Beaver Patriot Thunder
2012 Sunnybrook Harmony 21FBS (SQEZINN)
2007 Jeep Grand Cherokee Overland