I live off grid too and in North Dakota so my diesels have had to be started on some really cold mornings with no block heaters.
What works for me is to make absolutely sure all glow plugs are working perfectly, engine is tuned perfectly, valves etc, battery is the highest capacity I can fit under the hood and when it's really cold I keep it in the house until I need to start the car. Synthetic oil has made a huge difference in cold starting as well. When I am away from home I just leave the car running, sometimes for days at a time but that's when it's well below zero. I have run my 500,000 mile 300SD at -58 below zero, with almost -90 below zero wind chills, the secret to starting it when it's that cold is to start a fire under the oil pan. In my garage I have a pit for oil changes etc, and I have a wood stove down in the pit so when I want to go somewhere I go out with an armload of kindling or sticks and start a really hot fire in the stove, which is directly under the car when it's parked in the garage, in about 20 minutes I can run the defroster without even starting the car and of course, with the engine plenty warm it starts just like a summer day. For when I am not parked in the garage I have one of those propane weed burner torches that I keep handy, light this and carefully place under the engine so it doesn't melt any electrical or rubber parts, in about 10 minutes both the oil and the engine are warm enough to start perfectly, even at -20 below zero and an added benefit is the transmission gets a bit of heat too. I have used gasoline in the diesel mix to keep the fuel from jelling but I prefer mixing kerosine. Usually I just run #1 fuel with an additive for lubricating.