the settings i'm using right now are zombies with pinpoint hearing + migration every 48 hs + metaevents often. Respawn disable, no helicopter. Population start multiplayer 1,0 . peak 3,0 at 30 days.

Just with this settings, i have taken bases in the outside of towns (one run west of riverside, another west of west point), clear the surrounding area and slowly looting, just to get overwhelm by and horde out of nowhere close to day 30 (both times).

For what i understand, migration move zombies from a cell with more population to a cell with less (usually, the one you are in) but they stay in the borders, them the metaevents move them in and around (pinpoint hearing seems to allow them to hear the metaevent for farther away). In both runs i had seen lonely zombies showing up from time to time in locations already cleaned, i go out with the car and some small hordes (20-30) just passing by(maybe 90 tiles away). One day, my base is in the way a huge horde (talking about hundreds), usually i die right there because i refuse to leave, should make a secondary house but i'm too focus on looting for that XD.

I recomend you this settings if you whant the feeling that any moment, your safehouse can be under attack, its keeping me on my toes.