A campfire at a distance would allow visibility of objects around that campfire if there were no physical obstructions. The limited distance to sight for the characters is only in reference to light in that characters area. Light sources in other area can and should expand that naturally. Go outside at night in the dark. Can't see much near you, but walk to a lighted parking lot, or a light on at a house. You can see things in that area because of the light, even if you can not see other things near you. Again, if there is some physical obstruction, then its the matter of creating the appropriate light wall to block it. Also be careful with these alternative light sources are not brighter than they should be. If you want to downplay it a bit for an across the map situation, reduce the actual light distance by half or a third even, until they get closer where you can reestablish the normal light. This would simulate seeing better detail for being closer while still seeing that there is indeed a light source in the distance.