Many soundbars have a smaller number of inputs in comparison to a modern home theater. However, I have heard it said that using your TV as a switcher is the best way to get around the limited selection of inputs. Is this normally as easy it sounds?
It is not hard to set it up because the cables usually have labels on what connection they need to be plugged in. If they don't have any labels, then the manual would be a big help.
Your plan should be easy to carry out, but some T.V.s won't allow those input options so you might run into trouble. Also consider that many modern soundbars utilize virtual surround sound processing and do a great job of mimicking a surround surround system. The audio is pretty dynamic. Maybe upgrading your soundbar would be a good option for you if the one you have is fairly old.