The 3 sisters consists of 335, 336 along with 337. It's a great 120 +/- mile route if you do all 3 roads. 337 has had stretches of road work for the last 2+ years, I doubt the work will end any time soon. Aside from that stretch of road under repair it's worth the trip. I've done that ride a handful of times and it's always a blast. Definitely a must do in the list of Texas routes. [moto]
A couple of things to watch out for:
1. Cattle guards, I think they're on 335, appear at the apex of a turn and on days with mist can pose a real hazard.
2. Popo, they're pretty much cool with bikers but they ride in Trucks (F-150 style) as well and can fool you into thinking they're a civilian if you're only looking out for the typical squad car.
3. Drop-offs.
When the signs states "10 or 15 mph" they really mean what they say. Some of those turn can be pretty scary since they're blind corners. Watch out for opposing traffic.
I'm probably forgetting some other stuff but either way it's a heck of a ride out there. BTW, look out for the homes with camels, giraffes and kangaroos.
