Yes but the periferico is better. I accidentlaly missed the turn one year and went through downtown.
As far as los mochis, there is a pemex immediateley north on the east side of 15, just north of the large interchange at the north end of town. Next to that pemex (north of it) is what looks like a chinese restaurant althoguh it no longer is. Accesible north or southbound. Pull in there go to the back and to the right and there is a huge parking area. It is actually behind the pemex and not visible from the highway. You will be charged maybe 50 pesos. We use it for caravans. Pretty secure as truck tend to park overnight across the entrance to it (you can still get out)