When you look at #'s close to C, for this exercise we will call C
186,282 MPS. This business of getting close to C to go interstellar is not what it's cracked up to be. Using that figure for C, and we are in a spaceship going 1 MPS less than C, or 186,281 MPS, you are effectively going only 305 times C. So if you go 152.5 LY away, it takes 6 months according to clocks on the spaceship, and you spend say, 10 years at your nice new planet, go back at that speed again, you have been gone 11 years according to your calander, shipboard time. But when you get back, say you left in the year 2050, then you get back in the year 2365. You might think, wow, look at my bank account now, but after 315 years, your COUNTRY might not even exist, to say nothing of your children, grandchildren, great-great-great-great-great-great grandchildren, all dead, at least with our lifespans. Maybe in 300 years humans live to be 1000. Wouldn't THAT be a trip.
Come home, find your wife not only still alive, but looking younger than when you left, say you were both 50, she gets a youth treatment, ends up internally as a 20 year old, while you come back and you are now 61. Bummer!