Yeah, I don't think there are any hugely significant changes in DA that would affect the parts TA shares--so long as DL is updated enough for DA, it should work ok. I'm pretty sure though that the TA disc installer was supposed to update DA/DL to the latest as well.
In any case, you can do as follows:
To get the download version of the game (or the patch for a retail copy) up and running on an offline machine:
1) Install SDC on an online machine (keep a copy of the SDC installer handy).
2) Log in on SDC, head to the Games section, right click on the game, and choose Archive Application->Download and Archive. If the game is already installed and updated on this machine you can choose Archive Application->Selected Application to pack it up without redownloading.
3) If the game has modules (GalCiv2 does, for example), you'll be prompted to archive them as well. If the media you'll use to transfer the game isn't large enough, you may need to decline and archive each module separately; otherwise just say yes.
4) When the archive process finishes, you'll find the .sdc file(s) in C:\Program Files\Stardock\Stardock Central\BACKUP (this path is customizable in SDC's settings so it may vary). Copy the .sdc files along with the SDC installer to the portable media of your choice (CDR, DVDR, USB drive, etc).
5) On the offline computer, install SDC, then double-click the .sdc archive files in explorer to unpack them.
6) Run the game; you'll be prompted to activate. Enter the appropriate information and attempt to proceed; it will fail and offer you an option to activate by email. Copy the subject line and mail body it provides and get them back to the connected machine; email them off as directed, and follow the instructions in the reply to complete the activation process.
