In the 1960's Soviet ICBMs were liquid fueled and kept in shelters or pits with empty tanks. They required 1-2 hours to bring them in readiness for launch.
By the time Soviet ICBMs were ready to launch, they would have already been destroyed.
More than 70% of the Soviet bomber force would be destroyed on the ground.
The bombers that did get off the ground would be detected by our DEW line radars, intercepted and destroyed.
"No battle plan survives contact with the enemy"
Well you certainly seem to have everything all thought out. Except for what happens if you're not 100% successful in your first strike.
Keep in mind that the nukes in those days were not low yield tactical weapons capable of pinpoint accuracy. They were big and dirty. They had a huge blast radius and created massive fallout. Even if a handful got through, the destruction would have been enormous. You're also just targeting the weapons we knew about. Considering the multiple failures of our Intelligence community over the past 60 years, are you really ready to go all in on the premise that the other side wouldn't have any surprises in store for us?
At the end of 1965 we had 800 Minuteman I and 54 Titan ICBMs deployed.
The Soviets had 281 ICBMs deployed.
That means we could target 3 of our missiles on each of their missile silos.
The Soviets did not have a ballisitc missile early warning system in 1965, so they would have almost no warning of this first strike.
The Minuteman missile could be launched in less than a minute (which is why it was called the Minuteman).
Soviet ICBMs on the other hand would take over an hour to fuel and get ready for launch.
We also had 384 Polaris SLBMs deployed on 24 SSBNs.
They could be used to take out the Soviet bomber bases.