I drove that road in the last of November with my 32 foot travel trailer behind my Dodge Pickup.
We had absolutely no problem. It is paved to just past Alfonsinas. then it becomes what is essentially a construction road for the construction of the new highway. It was rocky and rough but passable in anything with care.
We at times were down to a crawl. But it much more scenic than Hwy 1 from TJ to Chapala (except for the part around Catavina.)
I had left San Felipe on Baja 1000 race day. I was hoping to get to the intersection of Hwy one before the racers started heading north on Hwy 5 back up toward SF.
We were stopped at Cocos Corner and told we had to spend the night. So we did. Early the next morning they allowed us to proceed even though there were still racers coming up the road.
We were careful and at times in the mountainous area I stopped the truck to get out and listen to see if I could hear a race car coming. About 20 racers passed us that morning with no incident.
Tractor trailers also use this route.
I would definitely go that way again.