I think you'd struggle to fly that route without overflying somewhere which is (a) extremely inhospitable, and (b) Isn't ICAO, or if it is (c) frankly it would be totally unrealistic to provide continuous SAR coverage anyway. Being brutal about this, you'd struggle to justify somebody else providing your SAR cover if you are 1000+ miles from the nearest human habitation.
Having said that, the gentleman in question has some track record of this sort of thing, I believe that about 15 years ago he undertook one of the toughest sea-kayak routes in the world, in a very small team, after only a few months training.
My guess is that if he does get "mislaid" in the middle of nowhere, he'll emerge largely unassisted a few months later and write a bestselling book about it - that's the nature of the beast.
G