My dad’s done a few similar trips, his forte is doing them on something a bit more ‘interesting’ than a GS. Much to the dispair of everyone else in the groups who usualy has identikit GS/Africa Twin/other whenever they stop it’s always whatever bag of nails he’s ridden in on that get’s people round cooing.
MT500 – chain self destructed on the motorway, cam’s were a little ‘loose’ in the head, front brake was for visual benefit only. Did quite a few trips on that one!
Enfield 500 – suspiciously reliable as long as you treated oil consumption like it was a 2T.
Honda transalp (too boring and reliable), he bought it off one of the guys he’d doen a trip with, but quickly sold it.
Triumph bonneville (from the 80’s), same comments as the enfield
BMW R80 with a huge fairing
Moto Guzzi V50ii, once expelled a huge cloud of smoke from the exhaust, so he kept going, a few miles later it stoped (the smoke not the bike) so he sold it.
He’s now done the middle aged thing and bought a Harley.