Although I have driven 166 many times I have never driven it while towing. Actually just drove it a week ago and the road is good. I wish I could tell you what the grade for Grocer Grade is coming out of Maricopa. Best I can do is tell you that as you leave Maricopa it starts out very gradually for a few miles and then gets pretty steep for a couple more miles (just guessing at the distance). Most of the steep section has two lanes so traveling slow is not a problem. The down side into Cuyama Valley is a lot more gradual so no real problem. There are a couple of curves but no switchbacks up over the grade. Through Cuyama Valley is basically straight and two lanes but a good road. As dicknellen pointed out there is a park in New Cuyama on the south side of the road. Plenty of room to pull off under shade trees along the road to take a break if you want. As you get to east end of the valley it gets a little curvy but no real switchbacks. Mostly fairly gentle curves. There are a couple of very short and mild climbs up and over to 101. The route is traveled frequently by both trucks and RVs so it is very doable. Just a word of caution the CHP as well as respective county sheriffs do patrol and ticket speeders. Maricopa is not as bad as it once was (they got into a bit of trouble) but can still be a speed trap area.
