I totally don't get it. By traveling at "the speed of light" you would either be moving at relativistic speeds or in stasis. That is the generally accepted theory, and maybe it's just an alien-perpetrated conspiracy, but the hypothetical result is that the universe around you ages a lot faster than you do, things move fast, your ship can only survive so many micrometeorite collisions, etc. So basically you wouldn't be going anywhere near 5000 lightyears and all the life you'd encounter would probably live on near-human timescales. The only real differences would be body plan and societal development, so it would just be bizarro worlds like in the documentary Alien Planet. And that's as far as my perception goes. It's space. It's Star Wars.