Now I have my 1986 K100RS back on the road I am loving it so much I want to preserve it for as long as possible (50% spline wear on the shaft), so I am thinking of getting a K1200S to share the riding duties.

My question is, I can do all of the servicing on my K100 with no problems but the closest BMW dealer is over 4 hours away, will I be able to do some servicing on the K1200S and get the nearest map bike dealer to do anything I can't (even if I source the parts)?

Opinions welcome as I really would like a K1200S over a Honda Super Blackbird!

Hi Grant. Welcome to the forum.
Never owned a K1200S but did consider a K1300GT. However, went the whole hog and bought a K1600GT.
K1200S and GT's seem to very good value, over here anyway.
I don't see any reason why you can't do any regular servicing yourself based on what I have found with the K16. 
Just a matter of a bit of online research and taking your time. Getting at things under plastic panels is probably the biggest issue with the newer K's. If its the same as mine, the oil filter just screws on the side of the crankcases. Easy. 
Need a different filter remover, though.
Unless there's electronics involved, its just an engine after all.
Believe a couple of the main issues with them were the cam chain could jump the sprocket. There's an easy mod to prevent that happening.
Other thing was the fuel injection was supposed to be less than well developed. Understand the best way to cure it is to fit a Booster Plug.
I fitted one to my K16 to smooth out the throttle. The 'ride by wire' could be a bit on or off at the start of the throttle.
Must admit I would prefer it to a soulless Blackbird.

I owned a 2005 K1200S from new for over 37,000 miles. Changing oil, filter and other fluids is a cinch. Changing spark plugs and/or checking/adjusting valve clearances requires radiator removal then pressure re-bleeding. However, they are quite reliable. Mine I sold to a Canadian friend in '07 who's put over 115,000 miles on it since. He's replaced three of four ignition coils, an ABS sensor (not a fault - a tyre tech damaged it) and a shift fork in the cassette-style gearbox.

I went 175 mph (indicated) on it on the high Plains of San Agustin in New Mexico near the Very Large Array satellite dishes. What a serene, stable rush. The thought of errant tumbleweeds, coyotes, rabbits and armadillos slowed me...returning to sanity, at 100 mph it felt like I could just step off.

The cam chain tensioner issue is a factory recall. Be sure it's been done before you lay down your dosh. The on/off throttle was partially cured by software updates. The simple Booster Plug is a good idea. I've done it to my R1150RT & K1200GT. It 'fools' the ECU into thinking it's cooler air in the airbox than it actually is, hence, a slightly richer fuel mixture results throughout.