Other than CHIM and Mantling... is there much written about the other remaining ways of ascending to godhood?

Daedric marriage.

Umaril the Unfeathered married Meridia, and was half Ayleid/Half Divine as a result.

Violence, and something about irritating the sun with a stick I think...

try the 6 walking ways: http://www.imperial-library.info/content/walking-ways-0

Dracochrysalis is another way.

well using heart of Lorkhan as shown by Almsivi and Dagoth but that way is closed now.

Useing numidium as shown by King of Worms.

Mantling as shown by CoC

CHIM is something diffrent as it's not really ascending to godhood,

A question for the more knowledgeable... is the Yokudan Walkabout the Second Walking Way?

Mass genocide and unmaking the world avording to the Thalmor.