Morale in Cthork works a little different than Morale in Mork. It's d20 vs a DR of the Morale score. The gadabout isn't particularly brave, and so is at a 17.
For the sidecar and pillion seat, I couldn't find historical prices, but scaling based on modern prices I'm going to say $30 each. This makes a three person motorcycle cheaper than a car ($180 vs $250,) but lower carrying capacity, less sturdy, and you really don't want to crash in the motorcycle (in the car, everyone gets to test to avoid the damage. In the motorcycle, everyone just gets hurt.)