Save As with suggested file name and folder

I would like the user to be able to press a save button on the pdf and the "Save As dialogue box" pops up pre-populated with a file name and location choosen. The user can then choose to name the file something otherwise or select a new location. I would just like to save them the steps of copying the field data and finding the correct folder (deeply buried on server) however to place the finished document in.

This doesn't seem to require a trusted function, but how do I suggest the file name based on a field name in the document. And how do I suggest the folder the document should be saved into?

Thanks in adavance.