As a producer, what kind of metadata should we be thinking of including?
As a producer, it's important to be part of your organization's metadata strategy (if you are affiliated with the station that will be distributing your content). If you are an independent producer, your contacts at PBS, APT, NETA, or the appropriate station will let you know what information they need, but you can see what the priorities will probably be by looking at the Required and Highly Recommended fields laid out in the Co-op's recommended Metadata Model.
Each organization will have to figure out what workflow is best for them, but consider, for example, your role in providing metadata for the Entertainment Identifier Registry (EIDR) (see below), which should get published much sooner in the content distribution life-cycle than, for example, program listings do.
For now, be open to talking through the metadata strategy with others at your organization or with the stations or distributors you work with, and start taking steps to get the information (all of which you already have) organized in a way that will let you provide it sooner than you are currently. Making sure your program is listed in EIDR, on your distributor's website, and elsewhere as early as possible will give your content a competitive advantage when it comes to content discovery.