Welcome to the forum, Bkings. I bought an '02 LTC, and saw a lot of this Country on it. It also introduced me to this forum, which I am forever grateful.
Having said that, the BMW K1200LT is a rolling contradiction
You mark my words. You are going to have many "Wow! This is an AMAZING bike!"
moments. And shortly after, you'll have several "What the $%^* were they thinking???"
moments. It's a fantastic long-distance tourer, that does pretty darn well when the roads get a bit twisty. But it is no sportbike, and it does not have the reliable or dealer-network that the Jap bikes have.
As for the blinking ABS lights, I'm betting on simply a low fluid issue. That rear brake reservoir is often over-looked. It's a bit hidden under the frame rail. Add a few ounces of fluid, and you'll probably be good-to-go.
Speaking of the brakes ... under 10-15 mph, REAR pedal ONLY! Over 15mph, using the front level.
Tires ... watch your pressures. The more the better for optimum mileage. Let the pressures drop, and the LT burns through tires, front and rear. Then again, if you're used to Jap sportbikes, you know what it is like changing tires every 4-6K.
But you can get 12-15k out of a set of tires on an LT with proper (read: HIGH) pressures.
Yeah ... your father-in-law is a pretty cool guy. A friend bought me a bike once. That's something you'll NEVER forget!
FWIW, I'm currently riding a Kawasaki Concours14. After the LT, I bought a new K1200GT in '06. It broke down on my in Neveda, so I returned to a Jap bike.