-A religious component be able to keep them from spawning inside my camp. Maybe a trinket a shaman or priest can make that I hang by my gate as one example. (Courtesy of Book)
-zombies will gather nearby and craft in their cities however as they will travel in groups at these times it will be tough to raid them and most times require a group and you will still have a high chance to loose.
The hard part will be the difficulty curve. A new player who has just rammed his first totem into the ground somewhere in the mountains needs to be able to survive while a whole tribe of high-level players still needs to find a challenge. The threat level of zombie attacks needs a lot of variation. Both new solo players and large tribes of high-level players need to find an appropriate and survivable challenge. (courtesy of Larsa)
A means to this end could be to have a variety of specie of zombi. Zombis could gravitate towards certain camps based on the levels of and number of members of that camp. If the tribe is a new players homestead, it would attract maybe 2-3 low level zombies per day. However if a tribe has 20 low level players, 10 medium lvl players and 2 high level players, a hoard consisting of 40 weak zombies, 20 moderate difficulty zombies and 1 or two boss-level zombies.
Some of the different types of zombies could include
Mindless types, which are fairly weak.
Mutant types which are warped from the radiation. Could be weaker, but super fast. Or maybe slow but takes a lot of damage like armored zombie.
Some that are very smart, using weapons, guns, tools, magic etc other types of stuff. (Courtesy of MrDDT)
Some that are beffy and intimidating like the SuperMutants of Fallout
Some that are like bosses, taking them down would be similar to a boss-battle. These could be like the SuperMutantBehemoths of Fallout, which are 3 stories tall.
Having few of these very powerful behemoth mutants wandering the map would be very cool. If you see one of these while out alone scavenging, youll have to run away and assemble a posse to be able to take it down (or just shit yourself). If you're in a big tribe you would all arm up when you see it on the horizon and go to war with its minions then attempt to take it down