We replaced the heavy sleeper/sofa with a Lazy Boy love seat dual recliner...it's lighter and we love it...same length as the sofa bed...then we canned the two recliners that came with the unit and put in a scissor couch bed...nice and long across the back of the 5er and will make a bed far more comfortable than the sleeper/sofa made..
Just take measurements, watch the weight and make sure you can get the furniture into the 5er..With the LazyBoy loveseat dual recliner set up, you can remove the backs and it's easy putting the unit in the 5er...With sleeper sofa, we opened it up and no problem with putting it into the 5er either....