Some spoilers ahead...
Actually, a fair chunk of the Force-related stuff in Dawn of Defiance can be deep-sixed without really messing up the overall plot. Chapter 4: Echoes of the Jedi (taking place in the Cularin system from the Living Force campaign) is by far the weakest of the installments, and is pretty much there as one extended bout of fanservice to Living Force players, to the point that I've heard of quite a few GMs simply skipping over that module and having the PCs acquire the necessary information (coordinates to where Chapter 5: The First to Strike takes place).
As for setting it during the actual Rebellion Era, you may also want to consider tweaking what the truth behind the Sarlacc Project is, since Vader's already got (or is in the process of getting) the Executor. There's also the matter that part of Dawn of Defiance is that the PCs have to at least make some effort to keep their connections to Bail Organa a secret so as to avoid drawing the Imperial Senator into Imperial cross-hairs, where as during the Rebellion Era there's not quite so much need for secrecy and they're going to have a somewhat more organized support structure in the Rebel Alliance as opposed to House Organa (which tries to stay more low-key and doesn't have the same reach and breadth of military resources that the Rebellion does).
Regarding game mechanics, you could probably convert the difficulties listed using a rule of thumb that every 5 points' worth of DC the module lists, that'd be 1 difficulty die under FFG's system. So a DC 15 check would be a Hard difficulty. The earlier suggestion of treating a -2 or +2 modifier as a setback or boost die respectively works well, and for difficulties that go above a 25 (I don't think there's many, but it's been years since I last really looked at the later DoD modules), simply upgrade the difficulty for every 5 points over.
Edited by Donovan Morningfire, 22 July 2014 - 02:59 PM.