i've been researching collapsible kayaks and the like for precisely this reason, i think a less densely populated island with a low total population will be infinitely preferable to the main land although its hard to settle on a location, im a long way off thats for true

.....but yes i agree i think post-event society will inevitably collapse and relapse into a much more basic form although the degree to which this will happen is nigh on impossible to predict, as is the nature of the event, i spose conjecture and ideas will have to suffice ay?
i think another reason people will go to the coast is probably fishing, whilst the skills of hunting and farming are all but lost to the common man, fishing is far more accessible and widespread to the masses so transport notwithstanding the bounty of food and water is another major reason people will settle coast ways