Can't be near some really nasty things, like fungal towers.
Can't be near an area with a ton of enemies. Even if they can't get to you, it slows stuff like sleeping and crafting down. Some places have enemies at a higher z-level, like towers or subways, and they are a pain.
Underground area for dealing with portal storms and helping to mitigate temperature issues.
A nearby source of water is nice. Underground even nicer.
Scrapable wood furniture or fences or whatever is nice.