I used to play far too much 7DTD. I'd only play on a server with other people, and then basically just mine.
Deeper,
and deeper,
and deeper ....
I'd basically live down in the mine. Zombies never bothered me, as I was too deep for them to smell, and at one point I had basically turned into a dwarf and built an underground village, complete with houses carved out of the rock, farms, wells of water, workshops, and a communal area for campfire sing-songs. Only reason people needed to go to the surface was to get wood, but we'd cut down massive areas of forest to stockpile the timber. There were a few people who would spend most of the day above ground: raiding the local towns/camps, collecting resources, hunting, etc. - but they would all come down to my dwarven city during the blood moon!
Yup, those were some good times.