Can an upright freezer be transported a few miles on its side? What about if its left in an unheated garage in freezing conditions for a day or two? Should it remain off for awhile after moving?
Yes, once you've moved it, you should let it sit upright for a while. Not sure how the freezing temps would affect recovery. Might interfere with oil etc returning to the sump. You could always put a space heater in the garage to warm it up while the freezer is equilibrating. A couple days sounds good.
The most important thing is letting the appliance sit unplugged till it warms up to room temperature, it could take over 24 hours with the doors closed and only a few hours with the doors open.
This warming up allows the refrigerant pressures to equalize in the condenser and evaporator, So there will be no pressure to force oil into the evaporator etc.
Then you can lay it down and after you get where you are going with it you can plug it in IMMEDIATELY after standing it upright.
I have participated in moving well over a thousand refs and freezers that were played down in vans and PU trucks and never had a single problem.
There are no shipping bolts etc that can be tightened on any ref and freezers since the early 60s at the latest.
The oil used in refrigeration sealed systems will flow at -20F so placing it in a cold garage will no affect the appliance.