How much fuel endurance do SW ships have?
The ICS says that a Acclamator has a range of 250,000 ly and a .6 hyperdrive; now the Falcon has a .5, and this seems to be "very fast", so .55 or .6 must be a normal-to-fast ship speed (and if .55 then .6 is normal-to-slow). Thus the 50 million c speed for the Tatooine-Alderaan run (which is a fast route) naively gives an endurance of 1/200 years, or 2 days.
Of course the endurance in ly may well be based on an average speed route, rather then being an absolute (i.e. in higher dust concentrations the fuel consumption does not decrease though the speed does), so endurance may be as much as 10 times this, with the range an average.
If the endurance is in fact, say, 20 days disregarding interstellar dust density, then the distance a ship can travel in intergalactic space goes up sharply (intergalactic space is barren compared to the interstellar dustball we call "empty space"), so speeds may well exceed the 50 million c observed for the comparatively dustfree, and thus fast, Tatooine-Alderaan run by a few orders of magnitude (10 to 1000, say).
Of course, if no such link between dust density and speed exist then the 250,000 ly range would stand unchanged in the intergalactic medium; but then the speeds on all routes in the SW galacy would need be near identical too, which is not the case, we observe 2 orders of magnitude between the Coruscant-Tatooine and the Tatooine-Alderaan runs.
Further the Acclamator is a troop transport, so is likely intended to: go to A, pick up and transport troops to B, then return to C for refuel/refit etc.
A warship intended for long(er) independent deployment, say, in the outer rim , would likely have 4-5 times this endurance, so even if the endurance is a constant disregarding route, the SDs probably have 1 Mly range, and Shrikes etc. likely ½ Mly. (this would still only give them fuel for 1-2 months of independent operations if interstellar dust densities are not a factor).
This ½-1 Mly range of course is not enough to cross an interstellar gulf, so fic writers will have to assume that dust density is a factor (or use wormholes etc.), which will stretch this range by a factor of 10-100+ in the intergalaxtic medium: fuel enough to cross to any neighboring galaxies, but once you enter a new galaxy the increased fuel consumption inside the galaxy will quickly eat away your ability to make the return trip (unless you bring slower fuel ships either in the first wave, or in a followup logistics train).
As for where to put the SW galaxy if you want to use this approach and stay consistent with our current knowledge of our home supercluster: It needs to fulfill the physical shape and size of the SW galaxy (~120 kly disk & type Sb or possibly Sc: the core needs be somewhat smaller then ours for the core worlds to survive), it also needs to be close enough not only to reach the Milkyway, but to make the Milkyway a reasonable target galaxy for the expedition (rather then "well, its the 12th closest large galaxy in that direction, so why not go there"), or some reason must be engineered for our distant run-of-the-mill galaxy to be specifically interesting. (Most probably some variant of 'knowledge that humanity came from the Milkyway being uncovered'.)
Below a table I copied during some research for a fic I will never finish; sorry the tabulators don't survive cut&paste (the rest of the Virgo Cluster is also possible, but suffers from the "12th closest" argument), the conclusion of it is that only M31 (Andromeda) & NGC4945 are reasonable candidates for the SW galaxy, everything else is severely flawed in some way, and there are no spot-on candidates at all within 20 Mly:
Intergalactic Distances & stuff
What is really needed is a Sb borderline Sc (due to the nearness of the core worlds to the core the core must be smaller then ours) (the SW galaxy’s quoted size of:) 120 kly +/-20% (the inaccuracy of these distance size measurements outside the local cluster) galaxy close enough for a SW ship to travel (a few Mly, so lets look at 20):
A list of Galaxies within 20 million light years:
1 2 3 4 5 6 7 8 9 10
Catalog Equatorial Supergalactic Group Blue Type Size Distance Name Coordinates Coordinates Mag kly Mly
RA Dec L° B°
N1313 03 18.3 -66 30 9.1 8.7 Ret SB? ~1.5 4.5 barred spiral galaxy structure
Milkyway: Sb (2e11) 0 ly [in Sagittarious from core from outside: in Auriga{5h15min RA ~63o}]
Galactic centrum: just to the right of the top of the constellation ‘teapot’ (by half its width)
NGC45 00 13.9 -23 10 271.4 +2.9 11.03 Sc 35 14.2
NGC55 00 15.0 -39 12 256.3 -2.4 Sculptor 8.42 Irr 45 4.9
M31,NGC224 00 42.7 +41 16 336.2 12.5 Local 4.36 Sb 140 2.6 (Andromeda, perfect shape, OK size/dist)
NGC247 00 47.2 -20 46 275.9 -3.7 Sculptor 9.67 Sc 50 8.1 (OK-ish shape, too small)
NGC253 00 47.6 -25 18 271.6 -5.0 Sculptor 8.04 Sc 70 8.5 (OK-ish shape, too small)
SMC 00 52.7 -72 50 224.2 -14.8 Local 2.70 Irr 15 0.2 (OK-ish shape, too small)
NGC300 00 55.0 -37 42 259.8 -9.5 Sculptor 8.72 Sc 45 7.1 (OK-ish shape, too small)
NGC404 01 09.5 +35 43 331.9 6.2 11.21 S0 10 10.8
M33,NGC598 01 33.8 +30 39 328.5 -0.1 Local 6.27 Sc 60 2.9 (Triangulum, OK-ish shape, too small)
NGC625 01 35.1 -41 26 257.3 -17.7 11.71 Irr 20 13?
NGC784 02 01.3 +28 50 328.8 -6.3 12.23 Sd 30 16.3
Maffei I 02 36.3 +59 39 359.3 1.5 Maffei 14.60 E >20 14.4
Maffei II 02 41.9 +59 36 359.6 0.8 Maffei 20.50 Sb >25 12? (Perfect shape, too small)
Dwingeloo 1 02 56.9 +58 55 0.0 -1.2 Maffei - Sb >25 16.3 (Perfect shape, too small)
NGC1313 03 18.2 -66 30 228.0 -28.2 9.20 Sc 30 12? (OK-ish shape, too small)
IC342 03 46.9 +68 05 10.6 0.4 Maffei 9.10 Sc 50 8.1 (OK-ish shape, too small)
NGC1569 04 30.8 +64 50 11.9 -4.9 Maffei 11.86 Irr 5 5.8
NGC1560 04 32.8 +71 52 16.0 0.8 Maffei 12.16 Sc 35 12.6 (OK-ish shape, too small)
LMC 05 23.6 -69 45 215.8 -34.1 Local 0.91 Irr 30 0.2
NGC2366 07 28.9 +69 12 29.5 -4.9 M81 11.43 Irr 25 11.2
NGC2403 07 36.8 +65 36 30.8 -8.3 M81 8.93 Sc 70 10.6 (OK-ish shape, too small)
UGC4305,HoII 08 19.1 +70 43 33.3 -2.4 M81 11.10 Irr 25 10.9
NGC2976 09 47.3 +67 55 41.3 -0.8 M81 10.82 Sc 25 14.8 (OK-ish shape, too small)
M81,NGC3031 09 55.6 +69 04 41.1 0.6 M81 7.89 Sa 90 12.0 (Good size, crap shape)
M82,NGC3034 09 55.8 +69 41 40.7 1.1 M81 9.30 Irr 40 12.0
NGC3077 10 03.4 +68 44 41.9 0.8 M81 10.61 Irr 20 12.2
NGC3109 10 03.1 -26 10 137.9 -45.1 Local 10.39 Irr 25 4.1 (perfect location, rest sucks)
IC2574 10 28.4 +68 25 43.6 2.3 M81 10.80 Irr 50 12.4
NGC3738 11 35.8 +54 31 59.6 1.8 Canes I 12.13 Irr 10 11.0
NGC4150 12 10.5 +30 24 84.3 -1.3 Canes I 12.44 S0 30 12?
NGC4214 12 15.6 +36 19 79.0 1.6 Canes I 10.24 Irr 35 13.4
NGC4236 12 16.8 +69 28 47.1 11.4 M81 10.05 Sd 70 10.5
NGC4244 12 17.5 +37 48 77.7 2.4 Canes I 10.88 Sc 70 14.7 (OK-ish shape, too small)
NGC4395 12 25.9 +33 32 82.3 2.7 Canes I 10.64 Irr 50 13.7
NGC4449 12 28.2 +44 05 72.3 6.2 Canes I 9.99 Irr 20 12.1
NGC4605 12 40.0 +61 37 55.5 12.0 10.89 Sc 30 16.9 (OK-ish shape, too small)
M94,NGC4736 12 51.0 +41 07 76.2 9.5 Canes I 8.99 Sa 60 17.0
NGC4945 13 05.4 -49 28 165.2 -10.2 NGC5128 9.30 Sc 90 15? (OK shape, OK size/dist: dist+20% = 18 kly & size 108!)
NGC5023 13 12.2 +44 02 74.0 13.9 Canes I 12.85 Sc 30 17.6 (OK-ish shape, too small)
NGC5102 13 21.9 -36 38 153.4 -4.1 NGC5128 10.35 S0 30 12.1
NGC5128 13 25.4 -43 01 159.8 -5.2 NGC5128 7.84 S0 90 12.4 (Good position, crap shape, good size)
NGC5204 13 29.6 +58 26 59.4 17.8 11.73 Irr 20 14.7
M83,NGC5236 13 37.0 -29 52 147.9 1.0 NGC5128 8.20 Sc 60 15.2 (too small & wrong shape: looses to NGC4945)
NGC5253 13 39.9 -31 38 149.8 1.0 NGC5128 10.87 Irr 15 11.7
Circinus 14 13.2 -65 20 183.1 -6.4 12.10 Sb 25 12? (Perfect shape, too small)
ESO274-01 15 14.2 -46 49 171.6 10.3 NGC5128 11.70 Sc 55 16? (OK-ish shape, too small)
IC4662 17 47.1 -64 38 199.2 8.6 11.74 Irr 5 6.5
NGC6503 17 49.5 +70 08 33.1 34.6 10.91 Sc 35 17.0 (OK-ish shape, too small)
NGC7793 23 57.9 -32 35 261.3 3.1 Sculptor 9.63 Sc 30 10.7 (OK-ish shape, too small)
Column 1: Name of the galaxy.
Column 2: The Right Ascension in hours and minutes for epoch 2000.
Column 3: The declination in degrees and minutes for epoch 2000.
Column 4: Supergalactic longitude.
Column 5: Supergalactic latitude.
Column 6: The group the galaxy belongs to.
Column 7: The blue apparent magnitude of the galaxy.
Column 8: The galaxy type. E=Elliptical; S0=Lenticular; Sa,Sb,Sc,Sd=Spiral; Irr=Irregular.
Column 9: Approximate diameter of the galaxy in thousands of light years.
Column 10: The distance to the galaxy in millions of light years from one of the references
Below[not included]. The error on these distances can be as large as ±20%.