So I had a sudden thought -
You are traveling along at 90% the speed of light, your transverse size is about as wide as a galaxy due to relativistic effects. So you go from one side of the space ship to the other. Have you crossed a galaxy in a few steps?
If you try to slow down in the ship, your width shrinks, so that won't work, but... If you get in a pod hanging off that side of the ship, then disconnect from the main ship and decelerate, have you crossed the galaxy?
If so, you only have to go really fast for a few seconds perpendicular to where you want to go, walk across your "transporter room" and get out.