The rovers can kick out at about 180 meters per hour. The only reason it's taken this long to get as far as they have is because scientists have had to stop and look at everything (of course, that IS the entire point, but I'm speculating here.)

80 kms would (in theory) be 444 hours of steady daylight driving. Of course, back here in the Real World, driving the rover involves a lot of analysis of the terrain, figuring out what you need to avoid, kicking in a drive sequence, seeing if it worked or not, and a lot of other issues. Also, I don't know how long you can actually run the drive motors before a fully-charged battery craps out. I'm betting it's a lot less than a full day.

So, here in the Real World, the actual 1-day record distance covered by a rover is (as I recall) only about 180 meters. Certainly doesn't suck for a working mobile lab and camera actually on the surface of Mars, but not that good for road trips.

So a slightly more feasible all-out trip to the rim would take at least 444 days. Of course, that doesn't count hunkering down for the winter, cool science targets, impassable ravines, or any mechanical problems.