Agreed, riding at the speeds mentioned or higher for long periods of time are completely relaxing on the GW. I've never achieved a speed at which I feel the bike is buzzy or even mildly taxed in any way. Nor do I have an interested in speeds higher than already experienced.
I'm in the process of planning a 7K+ mile ride this summer. I know how to travel on an Adventure bike. I have no idea how to travel on the GW. It's completely different and it's going to take some shakedown attempts.
Normally, travel looks something like this. Packed and ready for Alaska.
The GW has very small side cases. The top trunk pivots into the pillion seat, so the area where a duffel could be tied-down is low. For example, if I put a helmet on the back seat, It gets hit pretty quickly as the rear case opens. I really appreciate having my helmet and other on road travel essentials (gloves, maps,...) in the top case. I use that stuff on the road, and packing the top case full of stuff I only need to take into the hotel at night just doesn't make any sense to me. We've experienced a helmet stolen on a trip, so the back case is nice an secure when away from the bike at a stop.
I many have mentioned I saw a video of a guy who sold his GW and went back to a GS. His reason, he just couldn't carry all he wanted for a long trip. I understand. In that regard, figuring out how to travel for 3 weeks feels challenging. Part of me wants to just take the SAS. I know how to travel on that. But I know DM would be disappointed, and I'd really like to see what it's like to tour on the greatest touring machine ever built. I'll figure it out.