Let me give you some positives.
My wife and I have just completed UK - Ushuaia (Argentina) - Deadhorse (Alaska) - New York - UK. 53,000 miles and nine months.
We were two up with camping gear. Seven sets of tyres, three sets of brake pads, one set of fork seals and serviced every 4,500 miles. The bike performed amazingly and the only thing that broke was my GPS mount, once on the Carretera Austral (Chile) and the other time on the Dalton Highway (Alaska)
Much of South America was gravel and sometimes worse. I had the seat re-worked before we left the UK and we sometimes did 450 mile days no problem.
I Also have a BMW 1200 GSA and bought the KTM because I thought it was more suited to this journey (two up riding). I was right.