Get a comfortable replacement couch that will fit the designated space. Maybe even get a love-seat style that reclines. Forget about finding one that folds out to a bed. NONE are comfortable. And I've slept on dozens and dozens of hide-a-bed's in homes and RV's. None!
Instead, just get an inflatable air mattress that has it's own built in air pump and put it on the floor when you need extra sleeping space. We used an inflatable mattress on the floor in our previous camper because the fold out bed was so horribly uncomfortable.
Our current 5er has 2 opposing slides in the front living room with hide-a-bed, tri-fold outs that almost touch each other in the middle. They are horribly uncomfortable to sleep on. Problem solved.... we got 2 matching air mattresses and put them on top of each fold out bed. With just a push of a button they inflate and deflate. They worked great, but they work even better on the floor, and take up the same space.