SRD says that low-light vision lets you see doble far in starlight or moonlight. But just how far is starlight or moonlight vision? Nowhere that is stated.
Correct, It's not stated. It could be a factor in minimum encounter distance (see Traveling and exploration i think.) but I don't think it's covered there either. I'll see if I can find the thread where it has been discussed before.
Vision is unlimited without concealment. The only benefit of low light vision is in the effective radius illuminated by light sources. The light source itself, and the area it illuminates is visible from an infinite distance.
Distance isn't limited, but visibility of an area is determined by the prevailing light conditions there.