When we went to do the Campbells Soup commercial, we had to ride in to a remote campground ... about 10 miles of very loose, mostly single lane, windy, up/down hills road ... 2-up! It wasn't fun at all and even worse since we were a ways back of a cage that was kicking up a lotta dust. I would not do that without a very good reason and this time, money was being waved at me LOL
That was on the RSV
On the Wing, I have taken it onto gravel just to see how it handled .... no problem and even better with the Khumo car tire on the back.
Yet to try it on the Vic but I will.
There are times when a person has no choice either ... like a few years back when they were seal coating the highway ahead of us (we didn't know) .... extremely loose gravel on top of paved surface ... can be quite tricky.
It's a good idea to purposely get onto some gravel roads just to get a feel for how the bike handles so that when you get caught by surprise, you're not surprised. Or in your case, you will already know what to expect before hand and maybe feel more confident.