[stcredzero]

Imagine if we just worked on fixing up the place we live on already that has air we can breathe, abundant liquid water, and isn't inundated with deadly radiation.

Funny, but extremely high altitudes of the atmosphere of Venus could fit the bill in the context of places in the Solar System. Temperatures and pressures are around room temperature and pressure there. The thick atmosphere of Venus provides some radiation protection, and water can be extracted from the clouds of sulfuric acid droplets there. You couldn't directly breathe the air, but oxygen could be produced in-situ, and bags full of breathable atmosphere would be buoyant, so you could easily suspend cloud cities there just by using the atmosphere inside the environment domes.

[Something1234]

There's this real cool concept about a manned blimp that was produced by NASA a few years ago. It has a really cool video to go with it too.

https://www.youtube.com/watch?v=0az7DEwG68A

[nradov]

But without easy access to heavier minerals it would be essentially a dead end, useful as a research base but nothing more.

[stcredzero]

But without easy access to heavier minerals it would be essentially a dead end

People who have been thinking about this are way ahead of you. There are plenty of minerals on the surface. We should be able to build remotely piloted mining equipment using phase change materials (like water) to shed heat. To cool the equipment off, we just haul it back to the high altitude base before the phase change material tank runs dry.