I'm wondering, is there enough imaging data from satellite images from Mars orbit to say something about the terrain and grades (slopes) that Curiosity would encounter if it tried to drive to the top? If there are boulder fields or sloping sand, the trip might actually be very unlikely for example.
Also, are there any problems operating Curiosity at higher altitude? Is it colder up there, or are there other weather issues that might affect it? Can it run in a complete vacuum or are there some localized heating issues that do take advantage of the low pressure atmosphere so far below "sea level" on Mars?
If the drive took 10 years, would the RTG still have enough oomph to keep it moving up safely and communicating? Do comms with Earth rely on any satellite who's lifetime is limited? Could it even make it to the top in 10 years, or would it take much longer? Anything else?
below: "This image taken by NASA's Curiosity shows what lies ahead for the rover -- its main science target, Mount Sharp. The rover's shadow can be seen in the foreground, and the dark bands beyond are dunes. Rising up in the distance is the highest peak Mount Sharp at a height of about 3.4 miles, taller than Mt. Whitney in California. The Curiosity team hopes to drive the rover to the mountain to investigate its lower layers, which scientists think hold clues to past environmental change. This image was captured by the rover's front left Hazard-Avoidance camera at full resolution shortly after it landed. It has been linearized to remove the distorted appearance that results from its fisheye lens." From here, original description at NASA.