My wife and I rented an ST1300 to ride in the Smoky Mountains a few months ago, and it worked just fine. It didn't have a top box, but it handled very well. We rode it down The Dragon with no instability issues, but then again, there's not a lot of straight line riding in the Smokies. Just make sure you adjust the rear shock preload when carrying a passenger and luggage and you should be fine.
Besides, all the ST1300's for sale at my local Honda dealer already have the top box installed, so it must be safe to ride, because a dealer would never sell someone a motorcycle that is innappropriate for their skills and riding style (unless you're a squid with a learner's permit buying a new ZX-10R or ZX-14 for your first bike).
Besides, all the ST1300's for sale at my local Honda dealer already have the top box installed, so it must be safe to ride, because a dealer would never sell someone a motorcycle that is innappropriate for their skills and riding style (unless you're a squid with a learner's permit buying a new ZX-10R or ZX-14 for your first bike).