@pgandw
Normally I would have added more than IS MOTOR SECURED but I felt that was not being asked but for you I will.
It is best for a long trip that the motor be removed due to rough roads, added weight of engine particularly 4 stroke engines, weak outboard motor brackets, etc which would require emptying gas from internal gas tank of engine if possible or at least shutting off fuel line and let the carburetor run out of gas. If external gas tank, disconnect fuel line and let the carburetor run out fuel.
In some cases, the outboard motor bracket may be solid to leave the motor on the outboard motor bracket but you need to keep it from bouncing up and down by tying the motor in an up position to something on top of the transom but the responsibility rests with the owner.
As for strapping down a sailboat to a trailer, as a dealer I use to strap down the trailer no matter how far it moved
In rare cases to ensure stability of the boat on the trailer, store the motor in the v berth. However, that needs to be corrected quickly to include a10% safety factor on the trailer tongue