I am originally from Montana and now live in a place where there are no BMW dealer close by so I understand how one can feel anxiety about such bikes. I had a Victory before this and the dealer network is smaller than BMW . The bike was not very good either. bought my 01 GS 3 years ago and was warned about all the maintenance it would require. Since then, I have changed my oil every 6K miles, have put 40K on the bike, ridden to Montana 3 times, Seattle, Denver, St Louis, Dallas, San Diego every week, all the way to Honduras and back, through rain, mud, hurricanes, and 122 degree temps. The biggest failure on any of the trips was a tail light bulb. I did have to have the ABS rebuilt and that cost me $250. This bike has been the easiest to maintain, and most cost effective bike I have ever owned.
Yesterday I actually had some professional service done on the bike at Dave Campbell's shop. He said the mechanic that rode the bike said it runs good but feels like it has been ridden hard. It has. However, I am not sure what is making it feel that way other than needing new tires right now and getting the shocks dialed in (I just installed Jacugars). GS's are great bikes that can take a lot of abuse. It's unfortunate you have one needing attention at the beginning of a purchase. Get it fixed and ride it. Don't listen to anyone that tells you how much work it is going to need. They do not know what they are talking about. Their Harley's need more and don't log the miles you will.