Tenant is a hoarder, leaves personal items out in garage and takes parking spot

[Jorge Liang]

My dad (retired) has a rental property with a tenant that has been problematic over the years. Here are the facts:

The tenant leaves (more like litters) personal items like toys for her kids, bicycles, and others in the driveway to the garage. It was a huge eyesore. She has also refused repeated requests to keep all of her items in her rental. To mitigate/appease, my dad built a storage shed and personally moved all of the tenant's items into the shed. However, she still has a few personal items occupying the driveway.

The tenant also has occupied all two of the parking spaces. She was only assigned 1. She has refused repeated requests to stop and is defiant.

What can we legally do as landlords to stop this? We wrote some official letters but plan to write more. The tenant has ignored all letters besides being defiant over SMS. Are we able to able to charge rent for the occupied space in and out of the shed as well as the parking? Is towing also an option?