Bugout Boat
Remember the old Kevin Costner film "Water World"? In a WROL situation it may be quite as apocalyptic as that but here are some pros and cons and a link you might want to take a look at.
Pros:
-Isolation and relatively unreachable from the starving masses on shore
-Fresh water plentiful, assuming you have a sustainable way to disinfect it
-Fishing easily available as long as there's no environmental devastation or overfishing in your area
Cons:
-Entirely dependent on the water for your food, unless you can grow food on the boat
-Fuel/mobility issues (You would need solar and wind)
-Extremely vulnerable to inclement weather. (One bad enough storm and your floating BOL could be gone forever, maybe taking you with it)
-Cramped quarters/very little storage unless you're willing to tether a bunch of boats or platforms together ala Waterworld
-Limited access to plants you don't grow yourself
-Inability to keep livestock (maybe chickens?)
-What happens if you can't return to shore at all? What if the looters/raiders decide they want what you have, and camp on shore to wait you out? Hope you have enough to eat and drink until they get bored and go away--assuming they ever do.
I would consider this a short term solution unless you are on a body of water and boat that are both fairly large. Check out this link
Floating Cabin
Bugout Cave
Now I have heard a rumor that a large survival group purchased a area of land in Arkansas that is a side of a mountain with many large caves. Well it should be a good idea if our ancestors supposedly started there right? Well lets take a look.
Pros
-A large enough cave will give you ample space out of the elements and allow for you to have a fire.
-Very little maintenance needed
Cons
-Rocks may fall from the roof on you while you're inside.
-You may have to share your cave with the wildlife there has been there long before you (bats, rats, salamanders)
-Moisture dripping from the ceiling (but its better than being out in a cold rain)
-Caves may be very bad places to be in a thunderstorm. (the path of lightning as it travels down from higher up through the rock. As it travels past the cave, the lightning sometimes leaps through the air, across the cave where you might be sitting)
-Caves are a very bad place to be during an earthquake.
-If attacked you may not have an alternate way to escape.
Again these are suggestions/options that if you are considering as I always say..PRACTICE PRACTICE. This is not something where SHHTF and your realize you are claustrophobic or you are not a good swimmer.
Be prepared, not sorry
