What kind of game do you plan to run? Combat heavy, or more about survival in a harsh world? Action or Drama? Linear or Sandbox?
It was a long time since I had a group to run T2k with, and the only time I have been a player in a T2k was among my worst RPG experiences ever due to incompatibility between me and the game group I joined (it felt that they were running T2k as D&D, with the Russians as some form of dumb orcs. But as they were happy with it, I say it was a good game. Just not my flavor).
If I would find a suitable group, I would run a sandbox game (I never run per-packaged adventures, so any module is just "inspiration material" to me). So the size of opposed forces would be what I think would be suitable for a unit in that area, doing the task they are doing. That could be anything from a 2 man strong hunting party, to a 500 men strong armed force relocating (with a few hundred other armed men spread out and might hear the sound of any gun fight). But then, it would only be an opposable force if a) that force still have a grudge against their nationality b) it is a marauder gang and the characters looks as easy prey c) they have pissed them off earlier in some way d) mistaken identity e) or any other snafu that might make the situation hostile.
But I guess my sig says enough about the odds would be to run into a balanced encounter in a T2k game I would be running
If I would run a game today, I would either go with the rules from 2.2 or 2013.
I have not gone over the 2.2 rules in enough details to know what I would change there. But I like that it is compatible with Traveller TNE, so if I end up liking it I can also use it in SciFi settings and "cross overs" like Star Gate-esqu settings.
The rule set in 2013 is something I really want to like. But the more I look at it, and try to handle the parts I don't like (mainly the odds of getting certain results), I'm looking at a complete rewrite. But depending what type of game you want to run, those probability curves can work in your favor, as people not aware of it most likely will think they have a very different odds of success than they really have (on 3D20L, you have 14% chance of scoring a '1', almost 50% to get '4' or less, and 90% to get 11 or less).
Among the strong points of 2013 are the three different stages of the rules and a lot of options to create non-military characters.
Whatever version you pick, steal Wildly from the others to augment it
The movie
Defiance can probably give quite a few ideas for the setting
Edit: Perhaps I should add that my "problem" with 2013 is the combination of the probability curve, the curve ends at '1', and the positive bonuses are tied to the number of dices. Making it open ended downwards, and rebalance it, would probably do the trick for me. If the game is "competent characters surviving 'against the odds'", I think it will fit right in (5D20L gives slightly over 20% to score that impossible '1', 40% to score a '2' or better, and 55% to score a '3' or better, the 90% mark is around '7' or '8').