Assume we developed a perfect rocket, say a ramjet using a very efficient matter to energy conversion drive, within a few centuries. How far could settlers get with such a technology? The local group? Vrigo Supercluster? Laniakea Supercluster?

Given that the universe is expanding and that one would have to slow down again to settle a region, how far away is the farthest reachable place today?

I'm aware that the velocity and vector of the distant objects will be quite relevant in answering whather or not a specific target can be reached. So I'm looking for a rough boundary.

Can humanity reach any of these?