Clever, the simple fact that you posted this on Esther's & not Horn Depot tells me you really weren't taking this seriously enough from the beginning.
But you have come around.
Caveat: My warranty on your roof is null & void when you take a chainsaw to it. I also think the grit in the 30 year type shingles will seriously dull the chain. I see that you've decided to abandon the "house as an island in a sea of zombification" idea, so we'll just move past that.
I think a combination of Mac's large Flak Tower + your Martello's would make a nice community if it can be safely installed up near an Alpine area. You get the benefits of colder weather in more ways than just zombie prevention* & it will @ least slow down the undead in a summertime day with highs in the upper 60's.
You've got your ability to make water in times of snow, clearer lines of sight as opposed to the scrubby land in Texas, headwaters in the more moderate months... lots of benefits.
So, alpine region installation of a networked series of easily defensed towers. If you were able to secure a lake or two of sizeable dimension, this would be tantamount to having a maintainable fish resource as well as potable water.
Chainsaws - use for urgent building needs but then save for emergencies later on. Fuel will become a rarity, so don't waste it.
Buck saws, axes, hand saws, etc. Keep on hand & try to use for every day needs. Machete & misc. knives. Keep filing tools / stones on hand & learn how to properly sharpen equipment.
Wood. Limit fires to scraps where possible; save the longer, more solid pieces for construction & repairs. Become one with the mortise & tenon method as nails & especially screws will become a commodity.
Batteries. Even rechargeable batteries have a limited life span. Solar is nice, but again - battery banking only will hold go so far. Solar should be dedicated to direct power transferrance where possible. Which brings us to:
Radios. Hand held & hand crank is going to work best. Limited 2 way communication is probably going to be the norm as batteries progressively fade away. Try to establish breeding colonies of Carrier Pigeons for the safe transferring of messages & information. If towers are within visible range, binoculars / fixed telescopes & semaphores are going to really be the most efficient way around the battery limitations of tower to tower contact.
In the event of any type of overhead viewing (aliens, other cold region based scientists who have devised zombie repellant & have the ability to levitate or fly to outer regions & distribute this new product), we should also have written characters visible from the air or maybe even space (ex: see the somewhat recent thread about letters carved / written in trees out of a few hundred acres & visible from 20,000 feet). If you're worried about aliens bent on destruction, well there's no sense pretending you're not there because they'll spot your construction anyhow & won't wonder for 30 years if it's natural vs. made by an intelligent life form.
Weapons - for defending the towers, grape shot type short range cannonade is best; maximum accurate range of about 50 yards is really all you need as zombies mostly attack en masse vs. individual infiltrations (although Sylvester Stallone did make some serious coin on the idea of a one man zombie mission). I would also suggest a series of trip wires connected to bells or other non electric type early warning devices. 1 foot off the ground should be sufficient as zombies don't lift their feet & @ this kind of height, most people should be able to see it. Maybe use orange coated wire for better visibility & less rusting / degradation. Zombies don't care about color, it would seem, so paint away.
--Individual defense would suggest shotguns as being tops, as described effectively in prior posts.
--Reliability of a revolver vs. speed of a semi would lean toward a revolver (speed only induces waste of ammunition as described above).
--Long range rifles for harvesting food stuffs.
Medical care & triage - Mrs. Mac would probably be our best resource in this area, however there should be a specific set of guidelines as to what the gestation period is for converting to zombie-ism, what is mere drunkenness (i.e. a zombie-LIKE state) vs. a true conversion zombie-ness.
As for vehicles, yes - a 4x4 is going to be best & a horse, however novel & Red Dawn like, is just too much maintenance & a serious drain on water resources. On the one hand, I like the idea of a tube frame, heavily articulated chassis rig, aka a hopped up Jeep, however sometimes smaller & more compact is better. The drawback to an open bodied Mule or 4 wheeler is obvious should you have to plow through a massed crowd of zombies. For this balancing act of reasoning, I'll go with a mildly hopped up Jeep with 30" tires & a front or rear mountable (moves from hitch points) winch pulling an easily detached trailer with oversized tires on it as well.
More later as I think of it.
*Don't even get me started on the
Killer Bees. It seems their interbreeding with domestic bees has them moving into regions previously thought to be out of climatalogical reach.