T'Girl, I doubt Pike and Spock visited Talos IV, because the was no Enterprise. No Enterprise = no five-year mission. If they were on a different ship at the time, what makes you think they'd be assigned the same missions to the same planets?
Huh? The name of the starship affects her mission profile? Why? How?
If anything, Pike being in command of a radically differently built
Enterprise would ensure that he'd never get the same sort of missions he would have if he commanded a ship built like the TOS one (regardless of the name written on her hull). Obviously, two ships of significantly different size and design would not be assigned the same tasks - but two ships of the same design but different names would. And nuStarfleet could well have built the
Constitution class despite also building the
Enterprise class later on.
Also, it doesn't sound likely that Pike was on a five-year mission of exploration when he went to Talos for the first time. He wasn't exploring anything as far as we know: he was returning from a failed mission to Rigel VII, and later Trek appears to establish that Rigel VII was a known quantity and not an exploration target. Pike showed no interest in exploring anything in the course of the episode, either.
We could well speculate that Lieutenant Pike (as evidenced by his cuff braid), in command of a smallish second-rate starship of
Constitution class, was assigned a milk run to Rigel because Starfleet already suspected he would be a weak commander, easily giving up and succumbing to fruitless brooding. That Kirk Prime would achieve fame with the same diminutive ship would be all the more heroic, then. But again, it would be clear why Starfleet would combine a junior Captain and a small ship for the thankless mission of braving the galactic barrier: not because either of them was the best of the best, but because both were expendable.
Timo Saloniemi