Well put. Boundaries are necessary to motivate creative work, and for living in general. I too have a 2-year-old and am seeing this unfold just as you say.
I did pretty much what you’re talking about on the blog I began last year. In order to get myself writing at least a post per week, I forced myself to pick (at random) one of Brian Eno and Peter Schmidt’s Oblique Strategies, and write at least 750 words on it each week. It has done wonders for me. Not only do I end up doing it — whether I feel like it or not — but I am also finding it easier to just sit down and bang out a blog post in general.
The key seems to be securing a very specific topic, principle, or maxim to write about — one that rotates regularly. This way your mind is no longer exhausted searching for a topic to write about. You can literally just sit down, and write about what’s already been provided. Works like a charm.