I think it depends on what you, as the owner/driver, think about what situations you might find yourself in, and your comfort level of 'where' and 'how' to find outside-of-the-norm charging options:
I have several electrical items that I'm comfortable with - as coming from the 50amp RV'ing world, I've already learned how to 'wing it' when finding an electrical option is the need.
: 30amp 120v RV outlet to 50amp 240v plug adapter(not sure how the Ford Mobile Charger will be handling this, since it's designed for 240v at 30amp, hopefully it can still draw up to 30amps of 120v power), 30amp outlets are plentiful at campgrounds.
: 20' 8Awg 3-wire cable, with NEMA 50amp outlet/box on one end, open wiring on the other. This is for a situation where I might find direct access to a breaker panel, sub panel, etc.
: 50amp female to 30amp 240v twist-lock Adapter - to provide charging option from the bed's 240v outlet to another EV, or to my camper, etc.