Slow, cautious riding on gravel roads and relatively smooth dirt is fine and fun. As mentioned, anything else and you are limited by tires, ground clearance, weight and suspension. Even dual purpose airheads like the g/s aren't great in these situations unless much modified and prepped. But you should give it a try. Heck somewhere I saw a suzuki gsxr with knobbies that some character rode around the world.
"Between two explanations, choose the clearest; between two forms,
the most elementary; between two expressions, the shortest."
Between two motorcycles the simplest (DW)
Eugeni d' Ors (1881-1954); Spanish writer.