Climbed Snowdon today with four of the boys. Not easy (for me) but we made it. I'd been once before by another route. We used the Llanberis Pass. Quite busy. Cloudy on top but sunny before that.
Bonhoeffer uses a similar phrase 'worldly Christianity'. It's J Gresham Machen that I want to line up most closely with. See his Christianity and culture here. Having done commentaries on Proverbs (Heavenly Wisdom) and Song of Songs (Heavenly Love), a matching title for Ecclesiastes would be Heavenly Worldliness. For my stance on worldliness, see 3 posts here.