They completed a 7-season voyage before arriving at the spot in time for them to be blown up.
Let me go back in time, pardon the pun, and explain how I arrived at this idea.
I draw inspiration from Temporal Ambassador. How sure are we that this FE was in fact the 2nd time the Ent-C entered a timewarp and ended up at the wrong place? Explains all that fused Mk XII gear. They could have just not mentioned anything about their other "destinations" to avoid distorting the timeline further.
Even if it is, how are we sure that the Ent-C didn't end up elsewhere again after we sent them back in during that mission? After all, the timeline repaired itself eventually, but how are we sure that the timeline did not, in that space of 1 nanosecond, transform seven hundred and forty times before becoming what we now call the Prime 2409?
Enter a new FE/TV/movie series based on the temporal mishaps of Tasha Yar and the Ent-C, gallivanting through time and space, just to go back to the moment when they were supposed to die and save the Federation. Watch as they explore strange new worlds, encounter new civilizations, revisit major events both old and yet to come. Feel their anguish as their suicidal mission takes longer and longer to complete, where the emotions and wills of the Starfleet officers on board will be tested.
All to boldly go where no one has gone before.
And yet, no one will remember them, ever.
Might even link to Sela, and how Tasha eventually "became the concubine" of a Romulan senator. Maybe the senator was actually Castillo transmorgrified. Maybe the Enterprise-C with their 41st millenium weapons pounded the Romulans soundly, and then staged their ship's own demise to change the outcome without changing the past.
And there's more. Maybe Sela was in fact a child of love that got left behind in the chaos of the Ent-C crew's escape from Romulus? Maybe Tasha Yar is in fact alive and well, waiting for her time to return and give her little girl a good spanking.
And then Denise Crosby suddenly has a dramatic career revival.
Who knows? Its up to the writers on this.
And thus concludes another interesting thought I had tonight that I felt that I had to share.
That said, one of the Ent-C's mistakes should take them to a timeline where Daleks are EXTERMINATE-yelling anti-heroes fighting a desperate war against a Borg-Cybermen Collective that successfully assimilated the Q-Timelord Alliance.