Gonna add my fav spot too
Here’s my spot for starting bases (from ~10 to 60) up to the point where I need to get Star Metal and maybe move north:
There’s a big expanse of desert filled with trees and stones and fiber plants, and also dry wood, and there’s a small low plateu on which you can also build, and has enough space for a big base and to expand vertically.
You have access to the river through a round around route (following the “road”) or you can build an elevator as a shortcut. There’s lots of iron nearby (~ up to 9000 or maybe more, by going from deposit to deposit) and there’s lots of coal too.
Sinner’s Refuge and Gallaman’s are very near, and have enough brimstone to get you started… and the Deathwhisper Ruins has lots more, if you can deal with the quick spawning spooders there