Surley LHT or Trek 520. In USA, these seem to be the most popular. Seems people speak highly of their Surley.
I have a Surly Long Haul Trucker that I use as my winter bike .... great bike and very comfortable, especially if you add a decent saddle such as a Brooks Cambium C17 or a Gilles Berthoud Aravis (I have the Aravis, but have the Brooks on my Giant TCR)
I bought mine brand new, but it basically comes as a 'skeleton' .... i.e. crap saddle, no mudguards, crap pedals, no pannier racks, no dynamo hub/lights etc etc ..
add all these to the cost of the bike, and it works out pretty expensive. So my advice is that if you do want one, look for a 2nd hand one in good condition on
ebay that has the racks/pannier bags etc .... I have the Long Haul Trucker, but many say they prefer the Disk Trucker as it has disk brakes
also, it's heavy and it's slow .... mine has 26" wheels ... I'm still using the Continental tyres that came with it, but when I get new tyres next month, I will use Schwalbe Marathon Supreme (brilliant tyres that roll fast and have good puncture resistance)
I thought that I might do LEJOG with mine, but it's approx 5km/hr+ slower on the flats than my other roadbikes and that is when there is nothing in the pannier bags. It's very slow up steep hills compared to my other bikes, as it weighs approx 19kg unloaded
It does not sound like much, but if you cycle 10 hrs a day, for 7 days in a row, it makes a huge difference (350km in a week)
so, as my daily winter commuter, it's perfect (40km/day) .... I doubt that I would ever sell mine and will use it to go on a fishing/camping trip along the coast soon
If I were to do LEJOG or similar, I would most probably use my Specialized S-Works or Giant TCR with a decent handlebar bag, and a decent saddle bag and a credit card and travel light. If worse come to worse, I can always use a rugsack with a few light items
even an older Dawes Galaxy with 700C wheels would be more suited IMHO
basically, a Surly Long Haul Trucker is an old man's bike .... slow, but is as comfortable as a Cadillac