Access to the top of the van?
Aren't you the 6'plus fellow? !! Standing up on the rear
wheel, or on the front door step I'd think would give you
reach enough. (Or just chuck a small feller up there.
And, if so, could there be *fixed* lines eye-knotted to the
center fore/aft rungs of the roof rack such that one could
cast them left-/right-wards up over the (pair, I'm thinking)
ladders and then tie down to the rack's sides?
Anyway, having a decent sense of *knotting* --if not so much
an *indexed* knots set-- to call upon should indeed come in
handy. What sort of line are you working with --laid PP, nylon
solid braid, ... ?
Speaking of ladders, I've satisfied my desire to not fall over
when upon one, and to employ cordage at every opportunity,
by using guy lines when up on a ladder (this helps if being
paid by the hour
). With one long line anchored at either
end of one's working span, lanyards tied to the ladder can tie
to the long line with Prusik hitches
and enable one to bit-by-bit
adjust the tension and move the ladder laterally --i.e., lines are
only tight when up, then support one's reaches; then they're
loosened (one or the other side) in anticipation of the ensuing
movement left/right of the ladder.
The attached photos show some light-duty gutter-cleaning
(nearly *harvesting* --a couple whoppers sprouted up there!)
work on a very light duty ladder. Heavy duty salvaged jetsam
cordage served admirably.