As it was bank holiday we got the bus and tube down to Little Venice today where they had their canalway cavalcade and then walked along the canal to just before Regents Park and caught the bus home, stopping of for a late lunch en route. Great weather.
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.