A low mile '84 R100RS is a pretty safe bet.
Nikasil bores mean that all those years of storage haven't corroded the iron bores (there aren't any).
Low mileage should mean rear wheel drive splines are in very good repair. In fact, post '81 twin shock airheads use a cush dampened driveshaft that all but eliminates drive spline wear/damage if they're kept properly lubed. IF properly lubed.
Change all the fluids (forks, motor, trans, driveshaft, rear drive housing) and go through the bike cleaning all the electrical connector contact points (the cause of MOST of the service issues you'll have with a bike like this). Dissassemble and clean the carburetors and inspect the rubber diaphrams.
Think aobut fitting modern shocks: Works Performance work well and are priced reasonably. A Corbin seat is a nice addition, too.
With a clean bill of health the bike should be good for some travel. These are great motorcycles for serious distance riding/traveling. Smooth, effeicient, comfortable, quiet and fast.