Use Public Form for "New" item form

I am trying to do something a little odd. We have developed a HD for outside drivers. Tickets are only a small part of it and workflows are the major part. I developed a public form with many options for the driver to select which determines ticket type, assigned group, and workflow after doing different things for different ticket types (options). We need the ability for agents to open tickets on behalf of the drivers at times. I'd like them to use the exact same form to open a ticket as the drivers outside sharepoint environment uses. My first attempt was to replace the New form with an empty form with a single text field that they could type in the driver iD and submit it which would use the driver ID as a variable in the form URL which they are directed to on save. That didn't work because it opened an empty ticket and the text field value was passed in as NULL to the url. Seems simple but I couldn't figure it out. I also had an idea to remove the "Save" and "Close" button on the form and use a button with the onClick taking them to the form URL after putting in the driver ID...I couldn't figure that out either. Any help would be appreciated.