In case anyone is still interested. Rode the route today westwards (Artesian to Zumaque). Ray R is pretty much spot on. It's paved all the way through. There is a bridge over a stream at the bottom of the canyon, it looks like it would be submerged in any but the driest conditions, but is dry now. At the bottom of Zumaque, there's a sliding gate with a keypad, it looks like you could climb over it (3-4 feet high); while I was standing there inspecting the gate, a car pulled up behind me, the driver entered the code and let me through. Zumaque climb is not for the faint-hearted, average 10% with short stretches up to 15% and total elevation gain of 250 feet.