1) starships travel at multiples of the speed of light, via whatever means. distance remains a factor in travel time.
star trek fanon establishes warp factor cubed = multiple of the speed of light. that is, if the enterprise is at warp 3, it's travelling 3 x 3 x 3 = 27 times the speed of light. warp 6 = 216c. warp 9 = 729c. fanon has also had to come up with things like 'warp lanes' to explain how the enterprise can get to the center of the galaxy so quickly in ST:V, which more or less punts everything to option 3, below.
2) starships travel nearly instantaneously via wormholes. distance is not a factor, unless you have to travel to the nearest established wormhole first.
3) starships travel at the speed of plot. travelling across the galaxy takes as much time as a handwave, unless there are complications (jedi training, space battles, hyperspace drive malfunction, etc.).
choose your poison.