Think about ADDING insulation in the ceiling as well as under the floor, the exterior walls if you can. For our 3039 sq. ft. ranch house that I built myself, I used the passive solar method with R 60 in the ceiling , R30 in the exterior walls and floor. I sealed all air leaks with gaskets for doors, windows, electrical switches/outlets, exhaust fans, etc. Our range is propane, and thermostat was set at 68* and our monthly propane bill for the month in the coldest months of the year ( varies from 17* to 30* ) was a whopping $ 103 / mo. For the hotest months of the year ( daily range 100* to 115* our electric air onditioning bill averaged $ 350 / mo. while the neighbors $ 600- $850/ mo ).
Can you just shut off the heat and drain the pipes when you leave your weekend home?
You could put them all in one small room with a small space heater set on a low, but above freezing temp.
Hmmm...my husband shuts down our cabin and drains the pipe each time we're there. It doesn't seem to be that big of a deal for him.
There are so many things that can go wrong on one's land that we just don't know or be aware about. You see anything can be blown in onto your land by the wind. What about a clout that drops a few raindrops onto you land that could carry contaminants ? What about draining storm water from lands uphill/ upgrade from yours even miles away ? What about bugs, birds, rats, mice, wildlife, dogs, cats, cattle, sheep, pigs, etc bringing pathogens onto your lands ? What about chemicals or pathogens hitching a ride on your car tires, clothes, shoes , etc. from you or your visitors from work, church, school, friends, hardware , feed stores, etc. properties ? So your own produced food is running very similar risks as any commercially produced food. We just can't know for sure.
![:\](/styles/default/xenforo/smilies/side.png "side :\")
Instead of the delicious water 
from the community water company's 1200 foot deep well 150 yards up the road, it could be filled with contaminants. 
I could very well turn on the shower and set loose a stream of sulfuric acid. I can't dance naked 
out in the rain either, pollution is in the rain. I'd better not go barefoot as I might step in a tire track full of rubber termites with a hankering for human flesh. I may never go outside again as the bugs, birds, rats, mice, wildlife, dogs, (no) cats, (no) cattle, sheep, (in the freezer) pigs, etc (you forgot the horses) bringing pathogens on my land and giving me infections, 
bacteria, virus, boils, dandruff, 
pimples, bad breath, 
ingrown toenails, toenail fungus, cavities in my teeth, cancer of the common sense, blindness, arthritis, 
shingles, 
TV election coverage overload, and 
dementia. So I can't eat, I can't drink, I can't go outside....that means I'm stuck inside with paint fumes, sheetrock (imported from China) outgassing fumes, 
central air and heat sucking fresh air from outside....it's a conspiracy to kill me. 
YUP ... do you remember the National News reports a few years ago where they were reporting almost daily of the "acid rain " from the Mid West that was killing the forest trees in the Eastern States ? Scary huh ? Read some of the reports written by the Environment Protection Agency as a bedtime story and you will have nightmares. So how really pure and safe are our home garden produce or home grown meats ?Gee Bob, after that rosy description, I am reluctant to go take a shower.
guess I'll just go drink some chicken broth....
