You are quick today Keith! I posted just before you did (post #5 if you missed it). LOL! (It answered the comment before you made it.....)
Sam's idea is good with the dipstick heater for the rear.
I don't like those hose style heaters. They work.... kinda. Problem is they heat the water in the hose. Which has to transfer heat through the water through the water pump and into the water in the block.... and so on. The ones in the block are much better because the water in the block starts to heat, then the block itself.