Pure and simple, it's a stupid idea. Any clown can ride a Rocket and even novices can and have done it safely. A certain amount of strength and confidence is required to manoeuvre it slowly but once up and running it's not harder than any other bike. I'm sure she'd be able to ride one, BUT there's no substitute for experience and knowing how to deal with the unexpected on one of the most unforgiving bikes around.
Get her to try this. On a smaller bike - C50 would be perfect, about 300lbs lighter than the R3T - get her ride slowly with the bars turned just a little and then grab the front brake hard. The sort of thing that can happen in a car park when someone suddenly backs out. Unless she's dim, that should send a message.
If she does THAT; it's proof enough that she's dim.
Even a light bike will get real heavy real fast doing that.
I agree with most of what you're saying though.
The Rocket is far from a beginner bike.
I've been riding about 3 years and have about 50,000 miles on two wheels.
My first bike was a Vulcan 900, which is very much like the C50.
Second bike is the Vulcan Voyager 1700. With a good bit more power, weight and height.
The Rocket III is my third bike and I'm glad I learned a lot of lessons on the other two.
I've only put about 2k miles on my R3T but have had to ride out the rear trying to outrun the front on more than a couple occasions.
A slick spot starting from a stop is one thing; but a fishtail when shifting into second or starting to lose the rear when you roll on too hard as you straighten up out of a curve are serious pucker moments.
I'm sure it can be done; but it would take a
long learning curve of conservative riding.
Or maybe a steep curve with a couple of drops.
Scott