Obviously long-distance road and long distance offroad are two very different things. How do you plan to do Lejog?
I bought a Genesis Vagabond because it’s basically a 29er ATB and as such will travel medium-lengthy stretches of road comfortably. It doesn’t excel at road-touring though. For long distance road I would ideally want a longer stretch and different gearing. But I prefer to live with the ‘do-it-all’ compromise of a drop-bar all-terrainer simply because I wanted one simple bike to tackle the wide variety of terrain which is typical of my riding/transport needs.
Unless you are looking to beat records then I suggest any bike that is comfortable all-day long. If it was me I’d probably drop less than half a grand on a decent used 531ST touring bike. Galaxy, Dalesman etc. Most comfortable touring bike I ever had was a British Eagle Touristique. Like a magic carpet, even on our crappy roads. On tarmac, the Vagabond is a close-second for comfort, as I do find it very comfortable with 2″ tyres – but with 35c it’s a different beast and the Touristique was appreciably more comfortable on the tarmac. On unpaved roads the Vagabond (or similar) would of course smoke it (2″ rubber and discs-brakes). For long-distance light gravel/road (mixed riding) I’d probably still choose the old steel tourer.
That all said, for LeJog at least I’d be more concerned about saddle-choice than bike-choice 😉