Folk seem to pick the usual Triumph, BMW, the Big Four, KTM, Aprilia offerings. You get the odd nut who tried long distance adventure riding on a Royal Enfield, a jacked-up Harley or a Ural.
...How about Guzzi? I'm NOT talking about the Stelvio either! (I think the modern fascination with litre/1200 twins and triples a bit silly for real adventure riding unless you're doing all road miles).
I'm talking about the V7 derived Stornello. Think about it:
SHAFT DRIVE!!!
744cc twin, making a nice soft 45ish ponies with good torque in a linear delivery. Super frugal compared to the adventure juggernauts. Even with the stock tank (a very decent 21 ish litres) it is claimed you could have a range of UPTO 310 miles, though maybe 250 between fill ups is probs more realistic.
The bike only weighs 186kg.
It's lighter than a KTM 1190/R1200GS/Tenere/CRF1000/Capanord etc, but more suited to everyday longer distance riding than a DR650/XR650/KLR650 and has SHAFT DRIVE. It looks pretty easily adaptable for luggage. It is set up for the road, I guess you'd have to dial in the suspension for extra $s, but other than that...

There doesn't seem to be a lightweight, simple, frugal adventure bike fitted with shaft drive on the market. If only the BMW/Triumph 800s had the option...at least this Guzzi is a starting point.
You may claim it's not a true offroad bike - but c'mon, neither is a 150bhp Ducati Multistrada. The Guzzi is at least at the right weight and dimensions to begin with.