The RT is a good choice. I've had a couple of opportunities to ride one, and it's a wonderful backroad bike. I'm pretty lankey, so they feel sporty, and fairly compact to me, but then again I've ridden a couple of Gold Wings, and one Electra-Glide that each seemed too compact for me.
Different bars would have fixed that tho...
If possible, see if you can talk the missus into joining you for a test ride if you go to check out that Beemer, just to make sure the ergos suit her as well. IIRC, the rear pegs are a little closer to the passenger pillion than they are on a GS, but likely not as close as your KS.
Nice bike, BTW...
