I recommend just having her towed and checked out, my 2001 7.3 was terrible if the heater was not plugged in below 20 degrees.
The new 6.0 HCFM filter also acts as a warmer, which I am not quite clear on, (just read my book tonight). It's location sucks for changing, but two filters are better than one.
I will attest my 6.0 started after many long sub 0 nights in Ohio, we had no electric at Xmas and she was fine.
The book also says to ensure you above 1/4 tank a gas to avoid excess air in the system.
WARNING, be sure of what your doing opening any part of the fuel line on the 7.3.