out posts would have to be self sufficient. as for fuel nuke reactors"
The fuel itself is correctly irrelevant, for us to be undertaking *anything* like this patrol program we would need to have discovered a vastly more powerful energy generator.
However, we still haven't dealt with the problems of communication.
Let's say a patrol spot a heavily armed incursion into "our" space..... the fastest possible way for them to communicate that information would be to fly back and tell everyone (as we're reckoning on ourselves having at least light speed travel) as any signal transmitted by them traveling at less than light speed+ would take years to reach its destination.
So now our notional patrol spots this enemy and is forced to fly weeks back to the nearest starbase to inform them that they are under attack.... the problem of course is that we must also assume that the enemy is also capable of flying at such speeds, or why would they be attacking in the first place (it would take them centuries to arrive).
Space is just too mind-bogglingly big for this to be in anyway realistically plausible.
3.5 light years
I've just checked and everywhere I can see sets it at 4.22 light years away.