I had a '98 GS that I rode the crap out of. The last couple of years it was fix this, fix that, what now? The last big trip was from my home in GA out to Yellowstone and back last summer. I had a $2K+ bill to get it ready. The bike was good throughout. But, I got back and said "y'know, it's time for a new bike". Bought a lightly used 2010 GS and I'm happy as a clam. The new bikes are stratospherically (not sure that's a word) better. Of course you'll have these guys telling you that an old GS can be fixed on the side of the road by whittling a wrench out of piece of wood and replacing the starter from a '65 VW parked conveniently nearby, shit like that, but I'm not a mechanic.
Maybe you should just get a newer bike. I mean carburetors.... hello 21st century! A newer bike under warranty means BMW will pick you and the bike up, fix it, put you in a hotel, and the hassles are done.