Northern Mexico / Nogales entrance:
Sonora is on a big push to open up more areas to be explored.
Future Alternative new coastal route to San Carlos (Guaymas).
Some is done, some is not. Right now the new road is just opened to Puerto Libertad & there is still just the old inland paved road south from Puerto Libertad to Kino Bay. If the road does indeed happen south of Libertad to Kino along the coast, that will be an awesome stretch as it's mountainous too!
Easy entrance (Lukeville/points west vrs Nogales)
Avoids Hermosillo all together
More interesting ride along the coast (15D is way boring)
You can overnight in Puerto Penasco, Puerto Libertad & Kino too.