I would expect and plan for sewer back up / sanitation failure. Sealing off your sewer line from the grid should be a plan, after all other items have been addressed. A leeching field can be done with enough labor and or power equipment, centralizing sanitation down hill from your water supply and living quarters.
Regarding a hard to leave scenario. Try Roving mobs who have superior number, and firepower. You take care of family first AND ALWAYS SAVE enough bullets to take care of them. ESPECIALLY any females in the family / group.
Having a "lot of ham operators" doesn't mean anything
1) are they gun owners with enough ammo
2) Do they think or feel the same way you do
3) how much food stores do they contribute to the "neighborhood"?
4) Exactly how many other "Hams" will they be telling what your situation is
5) How many folks have they told you're the gun owner
6) How much dead weight do the hams and others in your AOO have.
While it's nice to have communication lines available doesn't mean or do anything IF they are not on the same page. Family down the block has a nice pre electronic ignition car. I wouldn't depend on his help for anything. WHY? Because he's an OBAMA drone and would the one of the first i'd shitcan off the street. But hey that's me.
One more item regarding "A situation that may force you to leave"
After reading One Second After and Lights Out read this novel It will have you rethink a Hard to imagine "worse case scenario" Really make you rethink it
http://www.amazon.com/The-Survivors-...life+after+war
http://www.amazon.com/On-Road-Book-A...life+after+war