You need to go test ride one. I have the standard Rocket and have been on several 2-4K mile trips with her and she handles it all just fine. 80 MPH is nothing and the Rocket is happy to cruise along at that speed, with PLENTY in reserve if you need to pass.
The Classic already comes outfitted with bags and shield. I would recommend the Triumph windshield lowers to keep air from coming up under the windshield. Also, if you've read around a bit, the rear tire lasts about 10K miles. Some people get less, and a few get a little more. Since there's not a Triumph dealer or a 240/50-16 rear tire on every corner, it's good to make sure you've got good rubber before a long trip.
I still have the stock rear shocks, but that is something I do want to upgrade and others will recommend this as the first change, I'm sure.