Sounds pretty good to me. However, I think you should resign yourself to the fact that cleanups are part of mowing. How can you mow a lawn that's covered in debris? Most lawns will need a spring cleanup. Sometimes it's just a matter of picking up some sticks and putting a bagger on the mower. Other times it's a matter of doing the fall cleanup that never got done. In the fall when the grass is still growing how are you going to mow it when it's covered with leaves?
Just keep in mind that any time you decline to provide a service that the customer requests you open the door for someone else to not only provide that service, but the services you are offering as well.
As far as the $13.5K that more than achievable.