[shiftpgdn]

Just 1000 years for a stationary observer vs 22 years for a astronaut under 1g constant acceleration. It's not that radical.

[aardvark179]

The diameter of our galaxy is about 100,000 light years. Unless you've got some way to go faster than light then you're 2 orders of magnitude out on your estimate.

[JoeAltmaier]

That's ignoring relativity! For the astronaut, travelling at near C, dilation will occur and it will seem to be less time.