I can’t quote reply, so I’ll do my best to respond as well as I can.
Regarding “Epic” - this is very subjective.

What I am looking for is to fly to somewhere in the U.S., land, do an overnight, get up and go a cycle the following day for a half to full day, dinner, overnight then back to the airport to fly to Vegas.
I would like to see a mixture of sea, trees, hills/mountains. I am not too interested in seeing the perimeter of a city, or a long boring ride which has very little change in gradient and change in scenery. Ideally, I would not need to drive to the start of the route.
Places like Tucson which has been mentioned is too difficulty. It would involve multiple flight changes to get there. But i appreciate the response.
I will check out San Fran and San Diego.

In terms of my cycling ability, I am currently averaging around 25km/h for a 3 - 4 hr solo ride. I will do for example, 75km with 900m to 1000m of climbing just under 3 hours. In January, my fitness will likely be similar or better (hoping for better, and I will be lighter).