Oh I like that bike, and what a fantastic trip! Thats a combo of a whole bunch of choices of roads and accomodations. Will he be camping, hoteling, or a combo of both?
The windscreen, panniers, and guards could be done easily. The slightly harder stuff would be footpegs, seat angle, and suspension.
EBR was messing with rear air suspension, but thats a bit much for a one-off. The spring rate would be fine for one person and a reasonable amount of stuff, backing off the settings might make it soft enough to be livable with the weight on it, and you could get some height with a simple bracket. The front would be a little harder but also could hold surprises. Maybe all it needs is longer fork tubes? Maybe Uly forks fit? Maybe Uly triples and forks fit? The way Buell/EBR builds bikes I bet they do!
Honestly you could do that trip on a Grom if you had the taint for it, what kind of guy is you buddy? Is he used to dealer service with free coffee and popcorn? Or is he ok to touch a wrench without whining? If he's gonna build a bike for this trip he better put some miles on it first!