Great pictures. I was a week ahead of you, and did a similar route. Saved potential ticket though, just carried on from Montezuma via Sahuaripa straight south to Yecora.
If you do this route again, take the turnoff just past Basaseachic, great road direct to San Juanito and you get to see the falls too.
Camping is good at Villa Mexicana as well ($10), but it does get cool overnight. Supposedly, they will be working on the road down to Batopilas for the next four years., so the route you planned via Guachochic and Yoquivo is the right one. Road is paved halfway to Yoquivo (and it is currently being extended) Rest of the way is good as long as there hasn't been any rain.
The other route, Samachique to Batopilas is much rougher and definitely impassable after rain.
Really enjoyed your write-up and the pictures.