I've just returned from the Pyrenees on my 1100GS (87,000 miles), had it serviced 2,500 miles ago and had the bevel bearings replaced as there was a little play. New rubber and front pads and 'good to go'
I took a spare clutch cable, 1 litre of oil, alternator belt and short ignition wiring loom. The belt and loom I had anyway and the clutch cable was taken because I'm still on the original.
After 1,600 miles the only thing used was about 250ml of oil