Here is what I would do...
1. Google map the property or if you have a go ilawn account use it and its tools to access the property size and its' tax value. This can help you get a general idea of what you are facing from the beginning.
2. drive personal car to the property and visualize the project. He might only be willing to pay $50. for a mow, but you can make up the difference if you point out the need for pre-emergent, post emergent, dead ornamental replacement, etc. Walk and listen to the potential client.
3. Scout the area for additional prospects while there. You may just open a whole nother market.
You can shear a lamb many times, but you can skin him only once!