Cheryl learned to drive big stuff when we bought our ski boat almost 30 years ago. She decided she would rather drive the truck and trailer than put the boat on and off the trailer.
We found an empty dept store parking lot and for a couple hours she drove around the lot and used the loading dock to practice launching. One unique thing about launching boats is the break over at the top of the ramp where the boat goes down but truck is still level so the trailer disappears for a short bit, especially with a low-profile ski boat on it.
She is perfectly happy riding in the motorhome while I drive but she has driven, even in construction zones with the narrow lanes, and she can drive anything we have owned including the boat. Because you never know what might happen and we used to 4x4 out into the badlands so if I got hurt she needed to be able to get the rig back out to civilization!