Do the same thing we all did some 20-30 + years ago when those same roads existed and the same services existed, but there where a lot more pay phones around then too...
I've been in the boonies loads of times and wondered what would I do if my truck just quit on me..... Just figure to somehow figure it out when that day and time happened and don't really try to worry about it inbetween...
I do try to keep my vehicles in tip/top mechanical shape so that helps too..
Other than that, stuff happens and if you worry about all the stuff that could happen to you, you would never leave your house... :)
Good luck!
Mitch