We strongly recommend adding detailed instructions on how to park and access the home. This ensures that your Pro can reliably and easily find the location to save everyone time.
Unless otherwise agreed to, Pros expect you to provide or pay for parking. When accepting a job, they are expecting that to be the amount earned and are not typically accounting for parking fees. This means you are responsible for providing parking of some kind to the Pros and are responsible for any costs associated with the Pro to get into your home, this includes reasonable parking costs when appropriate.
For example, if there is only metered parking available, then you would be responsible for paying the amount for the meter.
It would not cover parking outside the time of the job, or parking in areas that you did not designate. For example, if you tell the Pro to use the garage, and they park in a paid lot down the street, you would not be responsible.
You do not need to be home for jobs. In fact, the most important thing we recommend is making sure there is a reliable way for your Pro to get into your home. We generally recommend a garage code or a lockbox, because it is more secure than leaving a key under the mat (although you can do that too).
Here is a lockbox that some of our clients have used: http://www.amazon.com/Master-Lock-5400D-Set-Your-Own-Combination/dp/B0002YP1VC/