14 feet is sufficient clearance and not a very precise answer. It is unlikely that a C from CruiseAmerica is any taller than 12 feet. Basement models with floors 8-12 inches above the chassis framerails are usually still under 11-6. Mine is just under that, I use 12 for comfort.
14 is the legal maximum (some states 13-6) for travel without a permit. Nobody makes a C motorhome that needs oversize vehicle permits. Agents at CruiseAmerica shouldn't be giving customers fllip answers when they don't know the real answer.
But coming out of Brooklyn, you do need to know clearances, because there are low clearance parkways and neighborhood streets that trucks don't belong on.
