Steve,
I have a Gen 3 450h and in the local conditions you describe I would expect to obtain 26-28 mpg, in total silence, approaching 35mpg on your trips every 2 months.Again in serene comfort and silence.
It is not a matter of whether the car would suit the conditions it is more a matter of whether you would suit the car.......and I am sure you would!
Do let us all know how you get on.
Regards
John