This morning I almost abandoned the visual novel project, and had decided to quit the "I can't write" game jam. The project just isn't exciting me, and Ren'Py is being difficult, so I thought it might be time to move on.
However, after a bit of a pep talk and some advice from a Ren'Py veteran I've decided to stick with it and at least get something submitted.
To that end, most of today was spent rethinking my implementation plan to fit within the limitations of the engine, and making and implementing custom UI graphics. The next couple of days will be make or break on this project, so fingers crossed!