The hours on the shoulder of the day are brighter than most folk think. If you are shooting anywhere near the sun you will be stopping well down. If you are shooting away from the sun, the landscape will be well illuminated and the shadows will be mostly obscured. Even shooting with the sun coming in from the side the contrast range between illuminated and shadowed surfaces will be sufficiently great that opening up will not necessarily be an option. Only once the sun is below the horizon will you be wanting to open up for purely terrestrial subjects - the sky toward the sun continues to be bright enough that it is not possible to expose for both sky and land short of HDR bursts.
My bias would be to take the widest zoom range I could manage commensurate with wanting to capture vistas. In my case I would be choosing from the Tamron 17-50 (a bit short on the long end), the 18-70 lens from the D70 kit and the 24-85 (a good option since it's one stop faster than the 18-70, the subject is such that bokeh is not an issue and panos are easily enough done). I would be tempted to carry the 70-300 VR in a fanny pack, just in case it was possible to get the glint off the distant buildings of the Metro area. No matter what lens(es) I eventually took I would be planning on shooting panoramas throughout the ride as well as some HDR toward the end.
Of course, if it's overcast the game changes radically and the ability to open up becomes a major consideration.