For an accurate FS1/FS2 timeline, try this:
http://fredzone.unitedgamerscoalition.com/su-tehp_fstl.shtmlIt's as accurate as I could make it. There are only two errors in this timeline. The first is that the Colossus began to be constructed in 2345, not 2347. The second is that the NTF Iceni was originally constructed in Polaris and was later secretly moved into the asteroid base in the Deneb asteroid belt prior to the start of FS2, rather than the Iceni being constructed inside the Deneb asteroid. (The Iceni's database description specifically mentions it being designed by Bosch and constructed at the Freedom Shipyards in Polaris.) Aside from these errors, this timeline is as close to canon as an FS timeline can get.
Oh, and KT, the answer to your question about the time between the first appearance of the Shivans at Gamma Draconis (aka the destruction of the GTC Vigilant) and the discovery of the GTC Trinity in the nebula is likely this: no more than two or three days.
That's just a rough guess, but the GTC Trinity has defected to the NTF only ten days before being discovered in the nebula (Command mentions this in comm chatter during the mission). I figure it took the Trinity a few days (perhaps a week?) to get to Gamma Drac from wherever they were stationed when they defected. It probably didn't take them long to power up the Knossos, since Bosch told Capt. Romeig (CO of the Trinity) how to activate the Knossos.
Once the Trinity powered up the Knossos and entered the nebula, it immediately attracted the attention of the Shivans, who attacked the Trinity and left it for dead, then sent a Rakshasa cruiser and several wings of Maras to scout into Gamma Drac and then Capella, where they destroyed the GTC Vigilant at the Gamma Drac jump node in the Capella system. Right after the Vigilant was destroyed, Allied Command deployed the GTD Carthage (Orion-class) and GVCv Dashor (Sobek-class) to neutralize the Shivan cruiser and fighters, thus securing Capella.
Once this was done, the GTVA had to move quickly to secure Gamma Drac and the Knossos portal and had to move just as quickly to establish a secure perimeter when the GTD Aquitaine got to the nebula. So 2 days at most between the destruction of the Vigilant and the discovery of the Trinity would be my guess.