OK, I've not got the books in front of me at the moment so I am going from memory and not from what's written.
The emphasis of the game was had several focal points, the Kaefer War and life on Aurora, the Beanstalk on BCV to name two. That humanity had only
got so far is to me the great potential of 2300, the NSL goes 50LY from Earth, that's nothing! To quote the Good Book: "Space," it says, "is big. Really big. You just won't believe how vastly, hugely, mindbogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen..."
The published books don't detail space further out is kinda like saying that everything outside the 50LY sphere is Foreven, it's ours to write, just cos exploration wasn't detailed in the books doesn't mean it wasn't happening!
What we know now about brown dwarves throws the arms and fingers as written out of the window, personally I'd rather use BD's to link systems I want linked and leave the majority of them out of the picture: why break it? Better to acknowledge it as good for the period it was written in and keep as is. (And create a new setting with current info and move forward!)
50LY is stepping out of the front door and standing on your porch!
Coming back to the thread (sorry), exploration in times of war is going to be limited by money and resources directed to the war but on the arms far from the French with the other nations keen to gain the upper hand exploration to new systems and new resources would be a major undertaking.