Re: Advice for documentary submission to public television (PBS)

call em and ask. Programming managers vary. They'll at the very least tell ya what need as far as deliverables (this too caries at the local level). KNowing this TRT and break times, if applicable, will help you produce your master and may even aid in your producing the piece itself.
They'll not buy an idea. You'll need a finished show but they will happily give you info what to pitch once ya have it. You'll then know who to do that with as well.