I used his system as a base. There's a pretty nasty memory leak in the weather system that would crash my server every 6-7 hours. It has to do with once inclement weather, like a lightning storm or windstorm or something like that, is triggered. It never shuts off and continues to run even when PCs leave the area and eventually consumes all the available system ram. So, as more areas get inclement weather, more resources are consumed and the faster the crash.
As I recall, my fix was to hook the system into a variable that was already being set on the area that kept a count of the number of players in the area. If that number went to 0, don't run that storm any more. If the variable was above 0, keep the inclement weather running.
Not necessarily related to the campfire proximity, I know, but relevant to the system.
As to the proximity, you might consider expanding the affected PC to be a loop to include other nearby PCs as well. The way it is written now, only the PC who started the fire gets the warmth benefit, but any and all close PCs should be able to warm themselves to any fire.
I'm happy to help provide my code if you want. Send me a PM if interested.