No hypothetically about it, I started an NR ICW campaign (multi-era GC w/o the Empire of the Hand) last night, and everything was going almost perfectly - by week 20 I had fully conquered the CSA's high-credit planets, was holding off the IR in the south, and my economy was just waiting for a few mining stations to build when I saw Kaine's SSD all by its lonesome a jump from Ackbar's fleet (him, 3 MC80bs, a bit under 20 smaller ships making up a 40-something pop fleet). I decided Ackbar had just enough firepower with him to take Kaine, so I send them over - and mid-transit, Kaine is joined by Jerec's SSD, 2 Praetors, and a dozen smaller ships, giving them a 70+ pop fleet. How did I end up with that entire force destroyed? I ran.
Follow the Zsinj Doctrine - never fight a battle you did not choose if you can at all avoid it. My fleet retreated, Theirs followed, I ran again. They took one of those newly-conquered high value planets of mine - which ended up with Jerec on the ground, so his SSD wouldn't be in space. I'd managed to get another MC80b out, which linked up with Ackbar, but left him still too weak to attack an SSD with a large escort - until Kaine decided to leave his fleet to do other things. Ackbar's force smashed the Praetors and their escorts, Jerec died on the ground as I retook the planet, and Cracken's intel informed me that Kaine was still only two jumps away, and once again alone. I follow with Ackbar's force and take him out.
Xizer's got the right of it for the most part (though the Hand doesn't have HPVs
) - you want to bring lots of fighters along and lure them over your ground weaponry if possible. But the simple reality is that the NR and the Hand, until they have time to build up their economies and fleets, cannot take a massive PA or IR SSD-led force head-on without horrific losses. You need to outmaneuver it, outflank it, try and encourage it to break into smaller pieces so you don't choke on the mouthful.
P.S. Install instructions!
1) Download and run installer
2) At a point in the install process, it will ask you to confirm which directory to install to, with "C:\Program Files (x86)\Lucasarts\Star Wars Empire at War Forces of Corruption" being the default - and as a Steam user, that default is wrong. You will need to find your Steam games directory and put it in here. Assuming you used the defaults when installing Steam, your Steam directory should be in your Program Files folder, or Program Files (x86) depending on your PC (if you have both folders, it'll almost certainly be in the latter). In your main Steam directory should be a folder called Steamapps, in that should be a folder called common, which should have a folder called "Star Wars Empire at War", and that folder should have a folder called corruption - THAT is the target folder for the install. So, after all that searching, the install path you should have the installer target should be something like "C:\Program Files (x86)\Steam\steamapps\common\Star Wars Empire at War\corruption" (no quotation marks). Let the installer do its magic. To make sure it worked, check inside your corruption folder and make sure you now have the folder "mods" with the folder "Imperial Civil War" within it.
3) In your Steam library, right-click on Empire at War in your games list, and select properties. In the window that pops up, select Launch Options. In the box that pops up, enter "MODPATH=Mods\Imperial_Civil_War " without the quotation marks. Hit ok.
4) When you hit play, select Forces of Corruption rather than Empire at War.
5) Conquer.