((How far from what size city is it the safest to be?))
A 10 Kiloton nuclear weapon will vaporize metal for about ½ a mile and have a heat effect for about 3 miles. A 100 Megaton nuclear weapon will vaporize metal to 35 miles and have a heat effect to about 250 miles. I believe the largest nuclear weapon ever built and tested was about 60 megatons. As I recall, the popular strategy toady is to strike targets with multiple numbers of smaller warheads. The 100 Kt to 1 Mt are the most popular. I believe there are about 150 - 200 major cities in the US and half as many military targets. Please correct me someone if I am grossly incorrect.
((You suggest bicycle. What about horseback?))
Yes, horses are good if you can feed and water them. Also, it’s very hard to eat a bicycle.
((Should we be stockpiling guns?))
The answer to this is NO! You will draw a great deal of negative attention to yourself. I recommend become familiar with firearms. This means taking a safety course and learning to shoot and clean many different types. There will be plenty of guns around when you need them.
((What kind of people will be the ones least trustworthy?))
The people with the most to lose if the world changes -Camel through the eye of a needle?
((Is the conflict racial in any way?))
Not at all. In fact, I would say it goes a long way toward erasing racial problems.
((Does the civil war start in such a way that with this foreknowledge those willing will have time to remove themselves to safer locations.))
Yes. You will be forced to ask yourself how many civil rights you will give up to feel safe.
((Will you readily be able to identify the enemy.))
They will be the ones arresting and holding prople without due process.
((Does living near a river with a distillation unit take care of water problems?))
There is an odd saying that might be appropriate here. Safe is anywhere a hungry person can’t walk in three days. Water is important but you must consider that when people need it they will know where to get it. I would not plan on planting myself permanently next to a water source. Yes, distillation dose make water safe but the runoff is highly dangerous. Please remember that distillation is not boiling.
((How are the five people within the 100 miles contacted?))
The goal is to have a place to go other than your house and to be able to trust someone with your life. Foster those relationships now.
((Do communications stay intact.))
Main communication systems no, CB, sideband and non-repeating short-wave, yes.