Don't know about "Rolling Kings". Maybe a corruption of "Villikins", implying lovestruck youths? (Villikins and his Dinah 1850).

Walloping is interesting, derived from french "galoper" (to gallop) in its g>w form. Also meaning "boiling", as in "poultice-wallopers" (medical orderlies), this use appears to cease after wwII. Strange it should suddenly recur in the late 60's.
But "galloping round the Horn" - sounds reasonable, especially on those white horses (not six of them I hope!)
There is a related meaning of painting, particularly large surfaces, with whitewash, so perhaps the paint-roller allusion has some basis!

As to the "v" and "w" interchange in Cockney, the community has changed now, but from well before Dickens' period until about 1970 the population of the East End good description here contained many seamen, and traders, perhaps from countries whose languages (eg Polish), have no "v" sound, so they just did their best to pronounce it. (My friend's father owned a "Wauxhall" car) The "w" pronounced "v" is from those of German origin (Think "Bay-eM-Vay as J.S.Bach's musical catalogue numbers).(Or Villikins = Willikins = Little Willie).