I’ve got the text following a path, but I’d like the path to be the margin (effectively) instead. Can it be done, and how?

Nobody? Binners?

Draw a box. Use the pen tool to convert direction point (make a curve) Paste copy in box…if i’ve understood?

Whatever you do you need to make a box, whether it has curved sides or whatever and paste the copy in it.

Create an object be it a line or shape that has the shape you want to be the margin. Create a text wrap and lay the shape over the box containing your text.
Voila! Curvy edge…
Lots of variations but text wrap is the key.

Always assuming I’ve read the OP correctly.

Is that not just text wrap to a detected edge?

http://helpx.adobe.com/indesign/using/text-wrap.html

I need it so the text fans out. Imagine it as a picture of the sun… The text would be the rays of the sun, the ball of the sun being the margin.

TBH I’d do that in Illustrator

There was I time could have answered this easily. Sadly, that was ten years or so ago, and I’ve forgotten pretty much everything I knew. 😐

Time to become a consultant then…