A modified HDJ will get you over the mountain passes loaded at 70mph no problem, for quite a bit less than an LS swap or turboing a gasser. Gotta take in to account the HDJ premium though.
I just installed a one stone in my 80. I didn't need to modify the door card, other than adding some double sided tape.
This really helps me with my posture and not slouching while driving, resulting in less back pain on long drives. The 80 was not built for tall people.
Not sure if this satisfies the "B1" requirement, but I purchased metric diesel fuel line here and am happy with the fit and durability. Used the Flennor line specifically. Hose - Diesel - Page 1 - BelMetric - https://belmetric.com/hose/diesel/
Actually quite the opposite. I owned mine in the midde of the city and driving was pretty much the same as LHD. It gets awkward when you get on the rural 2 lane roads. You have to lean pretty far in to the passenger side to spot oncoming traffic when passing.
There are plenty of mechanics that can work on them, but you might have to order parts for the mechanic.
I just moved to 8500 ft, and the temps have been ~15 F the last few days. She's not necessarily happy, but with direct injection it fires up almost immediately. Some sort of block heater...
RHD takes maybe a week to get used to. Only problems after that are drive-throughs and passing on 2 lane roads. Most vendors make RHD parts, like Wits End and Delta.
I rebuilt a whole 1hdt, and almost everything was readily available from partsouq. More US suppliers like Cruiser Outfitters are...