I received a PM suggesting I read Niven's
Integral Trees. I respect Niven as one of the best (if not the best) world builders around.

I tend to find his plots & characters boring

and so I avoid his stuff unless he's teamed with Jerry Pournell.

In
Integral Trees, Niven puts his sealess/landless world it an atmospheric torus [donut] in orbit around a black hole [or neutron star?]. But the people in his world are weightless, a road I don't wish to travel down.
This means I will have to deal sometime with my physics problem: What kind of world can maintain a 1-G oxygen-nitrogen, body-temperature atmosphere if it has no solid or liquid core? Even our gas giants, with their solid H/He cores can only maintain an H/He atmosphere. My planet's core would have to have even more mass to maintain a oxygen-nitrogen atmosphere.

This is something for me to think about...later.
Meanwhile Ben, my main character, is playing hooky from work as a herdsman so he can search out a really important job. My task: figure out what this could be.