Truly, the only thing difficult is getting here in a hurry.

Anybody not in a hurry would have little more difficulty than we did launching Voyager or New Horizons. They would, of course, need to build it such that it would operate for long enough to get here, which would be harder.

Or, anyway, start operating again once it got near here. It ought not to be very difficult to preserve equipment cooled to 2.7 degrees above absolute zero, which is, notably, below the temperature where helium condenses. Maybe the boiling helium could be used to wake it up.

There's also a reasonable chance that the first immortal humans are alive today, depending on how optimistically you project maximum life expectancy curves with medical development. (There's also, of course, an extremely reasonable chance that they're not.)

The dynamics of "generation ships" change drastically with changes in human lifetime, including both the dynamics on board such a ship, but also the motivation to pursue it.

Looking at how crazy many folks get being asked to stay at home, I don’t give high odds to a generation ship of awake humans ever making it intact anyway.

Don't worry, they'll be overtaken by a 1kg lump of computers, self-replication machinery, and propellant crewed by sapient AI/digitised humans and offered a pickup. Virtual passengers only, though, sorry...

Probably a lot more comfortable for everyone involved too!

One can dream, eh?