Hi,
Congratulations for trying not to use your car for school runs, riding can be such fun for the whole family!
I've been using a Babboe cargobike for the last 18 months and I can tell you that however living in a hilly area, I find it great!
They have an electric assisted version that makes every hill and long rides pretty easy ( I usually carry a 3 and half + 5 years old + friends, scooters and shopping!)
In addition to the safety and stability these cargobikes have rain tents which allows me to use it round the year whatever the weather conditions.
You can have a look at their website
www.babboe.co.uk, it seems that a new version on 2 wheels has just been released if you don't like the trike option. They offer test rides as well.
Good luck and don't hesitate if you have any question.