moving rock in trailer in cold climate

Have you considered placing life items in several smaller containers and
placing each container in a bigger styrofoam box like cheap "cooler"?
You could also take with you a box or two of heatpacks - they keep
relatively high temp (105F) for more than 30 hours so if you place
2-3 heatpacks inside the styrofoam box near the containter with water
it will keep it from droping the temp too much...
Animals are relatively more resistant to colder temps than to hotter.
If you make the temp change to be slow and low temp not last too long
I would bet you will have very high survival rate. Also, think about
ventilating containers during the trip with some inverter powered
air-pumps but make sure air-pump is pumping warm air because you will
have significant temp drop with such cooling depends of air temp...
Goof luck.

What has possessed your mind to make you relocate from California
to Alaska?????? :-))