Despite OP beeing a nuisance here, he is right about the 1-2km radius. You basically can stay within the city you spawn the whole playtrough. There is no motivatioin whatsoever to leave the forest biome, well lootstage but as you also don´t get the higher gamestage bonus when staying in the forest you don´t need bonus for your loot. Not even for aloe or oilshale you need to leave the forest anymore.
TFP did a hell lot of work to make us loot all day, but seem to have forgotten about other biomes. And seeing that there isn´t much more to be implented in the game, i don´t have high hopes for anything to happen that will change that. I kinda feel like they do only test on Navezgane where you naturally have to leave the forest if you do the quests as every building only exists once.