Pheonix, lots of good thoughts have already been expressed but I have one question for you. Why do you want to go back to FL? I realize it is home but such a journey is fraught with peril and the odds aren’t all that great if you have to walk it. Having others with you be it walking or riding a bike is helpful in many ways and so that is a positive but at the same time you will only move as fast as the slowest of you. If any of you develop blisters from walking or get your inner thighs chafed riding a bike all day long, your forward progress will slow to a crawl. I have experienced both. I have taken 100 mile bike rides a handful of times, and unless all three of you are in really good shape and experienced doing rides like that, do not assume it’s not a big deal. Once I did it two days in a row with a group riding from the Canadian border to the MA border and I only finished the 2nd day due to sheer determination. It used every ounce of reserve I had to finish the 2nd day. No way could I have done it for several weeks. Additionally, your calorie and water requirements will be very high with all of that energy expenditure. Even driving can leave you stranded if the nature of the situation is such that State borders will be closed. One last comment on bikes, the folding bike idea is a real good one, but having owned and ridden many bikes over the years, the fit of a bike is really important in terms of whether you can just ride all day long comfortably. I own three bikes currently. Only one of them really fits me well. For short rides any of them are fine. For long rides I can tell the difference fairly quickly. Riding a generic folding bike is way better than walking but don’t think it will be easy to go 2,200 miles.
If the answer to my question is that your wife and other kids are in FL, then my next question is what is the nature of your set up there? Are you urban/suburban or rural? Would they be able to fend for themselves for the months it might take you to get home? If not, then is it possible for them to go to ND also, even if not to the exact same spot you’ll be in? If where you are going is one of those energy projects I understand that there are housing shortages, but maybe they could relocate to someplace within say 100 miles? In a true national level SHTF situation, odds are you’ll be far better off in ND than FL anyway so my bottom line suggestion is to think in terms of you and yours hunkering down up there if that is at all possible.
A final comment on the comments on hightailing it back to FL before the SHTF happens. We are the proverbial frog in a pot of water being brought to a boil already. There are enough hot spots around the world and threats to the US right here and now that we are already in the “rumors of war” stage.