Welcome to the forum!
That looks like a good plan for what you want to do. The one area that I'm unsure of, because I don't know which Austar HD box you have, is whether or not that Austar box requires a menu change to switch the audio output from HDMI to optical. If you can set it up to output audio over both, then I think you're in great shape.
To really make it easy for your wife (and yourself), you could consider getting a universal remote control that let's you program in macros (multiple commands that execute with a single button click). That way, she wouldn't have to switch video inputs on the TV, either.