What is the best overall workflow?

Plan, shoot, edit, export. Everything beyond that is about maximizing efficiency. For example, shooting your video doesn't mean starting on page one of the script and going in order toward the end. Organize your shoot based on the resources you have at the time. If you have all the talent, props, and gear for scenes two and five, shot them and worry about scenes one, three and four later.

In post-production, your main concern will be doing your best to avoid undoing work you've already done. For example, if you do a rough cut, then apply sound effects, music, and titles, then go back and do some more editing for a final cut, you may end up deleting some of the sound and graphics you've just made. Count that as time wasted!