The final cost was $5,206.72 (all local pine including boards, no plywood or glue, cedar shingles), and I partly took off about 2 months of work (working on this during the day) to frame it.
There are some photos here, though far more on twitter: https://simonsarris.substack.com/p/the-goose-palace
If you can stick frame a shed its certainly not beyond you to timber frame one. You'll need to read a book or two and buy a few hundred $ of chisels. But no part of it is fundamentally difficult. Before this project I've used my circular saw more for cutting down brush than building.
Some budget item detail if you want to build something like it: https://twitter.com/simonsarris/status/1592159452995944449
And more construction pictures: https://twitter.com/simonsarris/status/1584169368203956225