Be realistic? Because the scenario is so realistic? Just kidding. I would want to have a Mercedes Unimog for travel and lots of weapons and ammo. I suppose it would just be our family about 8 to 10 people and I am with JThomp42...a boat. I would want to get a good size boat and anchor just a ways off the shore. We would leave the Unimog parked at the pier for when we had to come onshore.
I would want to anchor off a very flat shore with little or no brush so you could see what's coming. We would have small speed boat attached for scavenger trips to the shore.
Along with a handgun, ammo belt, and a lightweight rifle, I would want a bludgeoning tool. Ever see the movie Last of the Mohicans? Can't spell the indian's name but he had this huge club and it had sharp things on the edges. It would make an awesome weapon.
I would have several dogs that were protective and would bark when anything was off base. I wouldn't be nomadic as I think that would be more dangerous. I would want to build a fortress of boats, off shore with piers - like the off shore drilling platforms so boats could dock and tie off there but also pull farther out to sea if something went wrong. We would may come up with a way to create a floating platform that could hold soil for planting food.