It shouldn't take that long to thaw your deep freezer and get the food back into it safely.  The best way to keep your food frozen is to put it ice chests  or even heavy cardboard boxes and fill them full, stack them on top of each other and cover with blankets or sleeping bags.  This will provide insulation.  Then once the freezer is empty put some pans of hot water on the shelves if you have an upright or place pans of hot water inside the chest freezer and close the door.  Let it set for about 30 minutes.  You will be surprised how fast the ice melts so you can easily remove it from the walls. It is a little trickier with an upright if the shelves have cooling wires so be careful not to damage the wires.  A hair dryer also works great to melt the ice on the shelves especially ones with wires.  

I always keep frozen bottles of ice in my freezer, like the ones commercial juice comes in or even just water bottles.  They come in handy to keep the freezer full at all times, so it doesn't use as much energy and also great in times of emergencies.  They are also handy this time of the year to put into your ice chest when you go shopping or on a trip.  These bottles can be used to help keep your food cold while defrosting your freezer.  

After the ice is gone from the inside of your freezer wipe it dry and turn it on.  You can put the food back in while the freezer is cooling down.  It will cool faster if you put the frozen food back into it right after it is cleaned and turned back on.  

I have three freezers, two chest and one upright.  The upright takes about 2 hours to completely deice and the chest about an hour if you use the hot water method.  

There shouldn't be a food safety issue as long as your frozen food doesn't completely thaw before you refreeze it.  

Good luck and Thanks for using Ask Extension

Nellie Oehler