RE: r1100rt v k1200lt
I just happened to sell my 00 r1100rt and Im buying a low mileage 99 K1200lt. My decision was based not on the quality of the RT because in many ways it is a better overall bike than the LT. The RT is a very comfortable sport tourer, but a sport tourer none the less. The LT is a pure touring bike, bigger fairing, windshield integrated luggage, sound system and the like. If you were coming off of a crusier or sport bike I'd say stick with the RT, but if you rode a wing you are used to the larger proportions, and weight.
Just to give you a quick comparison according to Motorcyclist magazine's own test numbers the 00 LT makes 83HP/75lbft of tourque and weighs in at 866lbs. The 05 R1200RT(the last bike tested) makes 101HP/78lbft of torque, it wiehgs in at 631lbs. The R1100RT's made about 90-95HP and the R1150RT's made 95+HP both weighed in a bit heavier than the 05 1200RT.
as you can see the RT has a much better power to weight ratio, but it is a sportier ride. The LT will be a lot more like your gold wing with way better suspension and handling. As far as comfort the LT is more comfortable to me and I only feel the weight in limited circumstances. I gues it all depends on your riding style and mine dictated a full dress touring bike, although the RT was fine in that department as well, just not as good.
To me the RT is a great all arounder, that is not as good as the LT on the long trips and not as fast and sporty as the rocket crowd in the twisties. It is an absolutely fantastic bike, but in filling many roles sacrafices are always made. Ive never ridden one, but Im told the 1200RT is like a can of whoop ass compared to the previous generations
All of the above is one mans opinion (except the info from Motorcyclist)