The Goldwing is hard to beat. My husband has one and on this particular trip, I just flew down to Seattle (didn't have as much time off), and we rode down to Sacramento and back up the Alcan to Alaska pulling a Bunkhouse trailor and it was an absolutely flawless and amazing ride on that bike, about 6,700 miles.
It's a '04, 1800 "we" bought used for our 30th wedding anniversary.
They are known to be able to go many, many miles with only the usual maintenance and tire replacement. He has ridden many other bikes, but this is the one he settled on because he doesn't want to have to worry about breaking down.....AND that 6 cylinder will get you up and out of some pretty sticky situations real quick and depending on your riding skills, is a very manuverable bike.....don't let the "size" fool you....he has lots of stories with other bikes pulling up beside him.....
No other choice in our book...

You are doing your homework, good for you!