Marylou,
Welcome to the world of RVing.
As an RV furniture dealer, we get your question a lot. Jim touched on a few of the most common issues , but most RV owners change out their sofas with Recliners, preferring to have two cozy chairs in lieu of an uncomfortable and never slept upon sofa.
If you have a flat slideout, you generally have more depth, and thus, more options like Ottoman, Euro Recliner footrests or the ability to recliner further back without a need to adjust the Recliner's placement.
A raised slideout restricts these options due to the depth they maintain. At the moment, we are actually removing an Easy Bed (aka J-Lounge) from a Class C motorhome"s Raised slide to accomodate two Stressless byEkornes Euro Recliners. Because the slideout's depth is only 30", we are framing an extension in metal, which will be wrapped plywood, hinged to the slideout, and wrapped in carpet to not only avail the owners a space to rest their Ottomans at the same level as their chairs, but also a draw bridge of sorts which will keep their chairs from falling over on the road when the hinged platform is locked in its upright position.
Before exploring what's available, measure the space you have to work with and the slideout style you have. Also note whether the sofa is there to conceal something, like wiring or a ventilation / heating system. Lastly, bear in mind that most sofa removals will force you to patch the floor below, after the bolts are removed.
Good luck and congrats on your recent purchase.