Hi Phil. Welcome to the forum.
There are several keys to a form with workflow.
1. Identify the user. Use an Active Directory Web Service or Code or mechanism to identify the person opening the form. This allows you to ID the person for auditing and tracking purposes. Validate that the correct person, the one who it has been assigned to, is opening the form. Lastly, you can automatically access there name, department, email, location, etc to use in the form.
2. Track the form state. Have a field in your form which gets updated at each step so that the form can show the appropriate view or elements depending on the state of the workflow.
3. Track each participant. The requestor and each approver should be logged in the form so that you can reference them again as in your case.
I would recommend submit these forms to a central location for safe keeping since email can tend to be lost.
I do forms with work flow all the time so if you would like to see some specific examples send me an email.