That’s exactly the reason our recently purchased boat has twin engines. I wanted something I could feel safe taking my family out in on such a large body of water. Chances are I won’t have any engine trouble but even less likely to have a problem with both engines simultaneously (divorced fuel supplies and batteries).
I’m anxiously awaiting our maiden Powell voyage with it in October.
That said we will be solo boat camping off-season for 4-5 days but I wouldn’t hesitate to be on a smaller ski boat for a day trip or with a large group or during the more populated time of the year. Whatever you have I can promise you’ll enjoy the experience on Lake Powell.