IMO, Charles isn’t terribly popular, and a de-facto Queen Camilla will be even less so. For the good of the House of Windsor, it would be best that the gap between Elizabeth and William is a short as possible.
She appears to have a rather dry wit. When she paid a visit to the US during Bush1.0’s term, someone made a mistake and didn’t put a footstool at the podium for her (the height of the podium was set for Bush, who’s significantly taller than the Queen), so all anyone could see of the Queen was her hat. A few days later when she addressed congress, the first thing she said was, “I do hope that all of you can see me today.”
Also, she got her grandsons to set up her cellphone for her and was rather amused by the humorous outgoing message they recorded.
It would have been funnier if the next day she had brought some stilts along. 
“Hi, you’ve reached Liz. Leave a message or we’ll CUT YOUR HEAD OFF.”
I once saw a short video about the Danish monarchy. It begins with an aerial shot of the royal palace; a phone is heard ringing, and then we see Margrethe II in her office. She picks up the phone and says, Dronning! (“Queen here!”)