The car can be intimidating for non-technical people. IMHO, I would set everything to as basic/normal a state as possible--eg set everything to how she has it in her gas car. Set climate control on Auto. Put the Navigation map on the top of the 17" screen, and the radio on FM on the bottom and set to her radio station (or whatever she likes). Turn the side mirror reversing thing off so those don't move when she puts it into reverse if she's not used to that. Try and get the driver's seat adjusted better (not sure if she's tall or short, etc)--you may need to do it with her as there's a zillion ways to adjust the seat. Set the headlights to auto--don't have to do anything but get in and drive!
I'd then say if she's comfortable driving it on side streets, then she can drive it that way until she's more used to the car. It is a bit disorienting at first I will admit--no engine noise, super smooth suspension, steering is faster then my previous car, etc. The car does have a lot of power and it comes on quickly, have to get used to pressing the accelerator differently.
And my lord if she's going to use cruise control, tell her about the 1 mph increase versus 5 mph increase when pressing the stick for it. (pressing it one click up gives 1 mph increase, all the way up gives 5 mph increase--scared me have to death when I found that out by accident)
Hope that helps, I don't know anyone who doesn't like the car after getting going with it.....!!
-m