Ok, let's dig a little deeper.
1. What has he done to make him RINO?
2. Regarding easy races, he seemed to do pretty well in 2010 in a three way race primary. He smoked Medina and a very well dug in and connected US Senator with relative ease, avoiding a runoff.
3. He's won 3 back to back elections for Governor, which is unheard of in Texas. As you well know, Texas has only had 6 republicans at the helm. Also, as you well know, Texas has tended to vote out its governors after 1 term. Perry's bucked one helluva trend, which nobody can say was easy.
Perry has been nowhere to be found on illegals or sanctuary cities. He has given illegals in-state tuition rates. Guardasil. Trans-Texas Corridor. Way too many special sessions, etc, etc.
He has been over and over the douche running against the turd sandwich. He has never had anyone challenge him that was worth a damn. This is about the only thing I can see that would help him if it was just him running against Obama. Perry would win just like he has in Texas against the likes of Kinky or that idiot Bill White. Texas went Republican in recent years as far as the "6 republicans" comment you made. He has actually had it easy. He got the job after Bush resigned and thereafter has run against lunatics or candidates that self-destruct on their own.