Transported to the Doomsday World! Red Alert: Zombie Warfare

Apocalypse, Red Alert, System, and Mass Recruitment

Stories Like Red Alert: Mass Troops, the Apocalypse, No Fantasy Elements, or a Base From the Start

Any recommendations similar to Red Alert: Doomsday? Nothing fantastical, and short or long stories are both fine.

Any Apocalypse Novels with a Lone-Wolf Protagonist? No RVs or Safehouses.

Any apocalypse stories? No RVs or shelters. I want someone wandering alone, who's cold and ruthless and acts decisively.