Thanks, folks - a goodly list to work on! We'll have to sit with a map and do some staring and thinking. Any further suggestions welcome, of course.
I've been to Vegas (driving). Gulp! Might be an experience to fly in there at night - we'll see. Not a place I'd want to spend much time, I fear.
Tucson is a good thought - we have a good friend who might be there at the time, which would make it a "must".
CharlieZulu - yes, it's 47455. The insurers have now banned Catalina and Sedona, so we can't go there. Catalina I've visited several times, but I did really fancy a stay at Sedona, so it may be a landing somewhere nearby.
San Diego does have a certain personal appeal but that will depend on how busy or otherwise that person is!
Chilli Monster - many thanks: you're in grave danger of being taken up on that! I'll contact you nearer the time - this sounds like a beer opportunity...