If you plan to drive from Kingman, AZ to Las Vegas, NV, check with ADOT about US 93. The road across Hoover dam may problematic for a 40 footer and you both will be delayed for a security check (about 30 minutres). I cross west through Laughlin to US 95 north to Las Vegas. It a little farther, but probably faster. This will all change when the new bridge is finished in a couple of years.
Larry