You can easily and cheaply run 12 volt electricity more than 1/4 mile. I use bare aluminum electric fence wire, sold cheap in 1/4 and 1/2 mile spools, strung high between cheap electric fence insulators far apart in trees or whatever. At 12 volts you don't need insulation, just start out with maybe 18 volts and put a current limiter in series - a 100 watt incandescent will limit the current to less than 1/2 amp even if the line gets a dead short. Your 5 watt solar panel provides less than 1/2 watt when the sun is shining, a wire can provide that much 24 hours a day if you pick the appropriate current limiter. Committees of Correspondence Web page:- tinyurl.com/y7th2c