I vastly (no, seriously, *VASTLY*) prefer a coolant heater to a "block" or oil heater. I've run a 'zerostart' brand for 17 years without failure or issue. Plugged it into a timer so that roughly an hour before first use it'd come on and heat. Worked amazingly, even down to -40.
Amazon.com: Zerostart 3309043 Circulation Tank Heater for Power Generation, Compressors, Agriculture, 3/4" Diameter Inlet/Outlet | cCSAus Approved and cULus Listed | 120 Volts | 1500 Watts : Automotive
That's basically the unit I ran, and yes there's some plumbing work involved, though there are some styles that replace a small section of the lower rad hose.
Having grown up in Wyoming with the other typical block heaters, I'll never go back to them.
That's basically the unit I ran.